Bosphorus Straight River Boat Cruise In Istanbul
Bosphorus Straight River Boat Cruise In Istanbul

Bosphorus River Cruises In Istanbul:


Location: Bosphorus River Straight
Cost: 15-20TL for Ferry, 150-230 TL for private tour.
Start: Eminönü Boat Dock (Bogaz Iskelesi).
End: Eminönü Boat Dock (Bogaz Iskelesi).
Time: 6 Hours (1.5 ferry each way with 2-3 hours of layovers).
Map Key: Purple is the IBO Cruise Line (website) & Red is the Sehir Sehir Hatlari Cruise Line (website).
Fun Scale: 8 out of 10

 

A boat ride tour of the Bosphorus Strait (Boğaz Turu) can be truly magical with its collection of stately homes, palaces, and Medieval fortresses.  Serving as an important ancient trade route connecting the Black Sea to the Mediterranean Sea, the Bosphorus Strait has just as much history as it does beauty.  Because the straight divides 2 continents, you’ll actually be able to say you visited the European side (Rumelia) and Asian side (Anatolia) both in the same day.  There are plenty of ferry tour options to take depending on what you want to see and the time of day you want to go.  Below we have put together a great guide to help you out with the cruise line options and a helpful map of all the best sights the Bosphorus has to offer.

Picking A Bosphorus Cruise/Ferry Company:

istanbul bosphorus river tour cruise boat

When selecting from the Bosphorus Strait River Cruises in Istanbul, the 1st choice is going to be what length of tour can you do on your schedule? Short tours last 2 hours and Full tours are around 6 hours. We have broken down our suggested options below into what length/type of tour they are.  The 2nd thing you have to decide is what sights do you want to see from the River and what ones do you want to see up close. There are dozens of companies offering tours with different routes and ports. The ferry options set routes and only cost 10-20 TL ($5-10) round trip while the private tour options are much more flexible but cost $70-110 a person.

We suggest that you stop by the Eminönü Dock/Galata Bridge area to pick up brochures and check the schedules before booking. The good ferries are geared toward tourists with cash snack bars, bathrooms and will have digital guides that tell you about more than 70 points of interest in 10 different languages. Tickets can be bought right at near the piers and they suggest you show up 40 minutes before the departure for boarding. The operators are spread out among several piers at the docks.


Top 4 Suggested Ferry Line Options:

istanbul bosphorus river tour cruise boat

1. Full Bosphorus Cruise (Uzun Boğaz Turu): IBO Cruise (website), not to be confused the IDO Public Ferry, has a great Full Tour with 30-60 minute stops at a couple great sites.  It leaves Daily at 9am from the Kabataş Docks near Dolmabahçe Palace, stops at Ortaköy for 30 minutes, Küçüksu Palace for 60 minutes, Rumeli Fortress for 60 minutes and Poyrazköy Beach for 60 minutes before returning to Kabataş around 5:45pm.  Hotel transfer, soda, snacks, lunch, a tour guide and all admission to the palaces you stop are included for $110 a person. It is a little expensive, but overall is still a good value for where they stop and what they provide.  They also have a Short Tour option for $60 from the same boat, where you skip lunch and the beach an get coach bused back to town from Rumeli Fortress at 1:45pm.  On the return trip, you can be dropped off at Dolmabahçe Palace, Galata Tower or Eminönü /Spice Bazaar instead of your hotel if you’d like to keep exploring!

Alternative Full Tour Option: The cheapest Full Bosphorus Tour is run by the public Ferry company Şehir Hatlari (website) and only costs 20 TL.  This 6 hour tour leaves at 10:35 from Eminönü Dock/Galata Bridge.  With a few quick stops along the way the Full Tour takes 90 minutes to get to Anadolu Kavağı where it has a 3 hour layover, then returns getting you back to the start by 4:30pm.  The layover gives you the perfect amount of time to have lunch in town and check out the ruins of Yoros Castle above the village.  This route is marked in Red on our map.  Make note that the Summer Afternoon time slot has only has a 2 hour layover on Weekdays. Consider ditching the ferry on your way back and using Bus 25 to visit Rumelian Fortress.  In the Summer (mid June-mid September) Şehir Hatlari also has a 2nd Full Tour leaving Daily at 1:35pm.

Alternative Full Tour Option 2: Dentur Avrasya runs a Full Cruise route under the name Pereme (website) which leaves at 11:15am from the Kabataş Dock near Dolmabahçe Palace and only costs 20 TL.  Since the Palace is open at 9am, you’ll have the chance to get a tour in before your cruise.  The route only has 1 quick stop on the way and gets to Anadolu Kavağı in just 65 minutes.  After a 3 hour layover it gets you back to Kabataş at 3:30pm.


2. Short Bosphorus Cruise (Kısa Boğaz Turu):
Perfect for people busy schedule who just want a taste of the Bosphorus, Turyol Ferry Service (website) condensed short tour that only takes 90 minutes round trip.  The tour leaves Daily from Eminönü Bridge almost every 45-60 minutes from 10am-9pm.  The condensed route does a quick stop at the Üsküdar Docks near the Maiden Tower before going looping past points 3-9 non-stop and returning to Üsküdar & Eminönü. Time: 90 Minute trip leaves Daily almost every 45-90 Minutes.  Cost: 12 TL Round Trip. 

istanbul bosphorus river sunset cruise

Alternative Short Tour Option: Şehir Hatlari (website), the same company we prefer on the Full Bosphorus Cruise, also has a short version that leaves from Eminönü once Daily at 2:30pm (December-March it is Saturdays & Sundays only). Unlike the option above, this version has its short stop at the Ortaköy Mosque Dock before completing the same loop.  While this takes 30 minutes longer than our preferred company, it does have better narration.


3. Hop-On Hop-Off Tour (Klasik Boğaz Turu):
Dentur Avrasya runs a 1 hour 40 mintue route under the name Pereme which lets you hop-on and hop-off at a few stops.  It leaves from the Kabataş Dock near Dolmabahçe Palace every 60 minutes from 12:45 to 6:45pm for 15 TL round trip.  The trip is basically an ungraded version of the Short Tour with quick stops at Beşiktaş then Emirgan (just past second bridge) before turning around and stopping at Küçüksu Kasrı and Beylerbeyi Palace on the way back.  With these options you could tour Dolmabahçe Palace in the morning, hop-on the 12:45 Pereme Ferry, hop-off at Küçüksu Pavillion at 1:45pm for a tour, catch the next ferry 1 hour later hopping off at Beylerbeyi Palace.  Time: 100 Minute trip leaves Daily every 60 minutes from 12:45 to 6:45pm; sometime ends early in the off season.  Cost: 15 TL Round Trip.

Alternative Hop-On Tour Option: Şehir Hatlari runs a daily commuter/passenger ferry route called Boğaz Hatti (website) which leaves Daily every 30-60 minutes from 8am-11pm every at the Eminönü Dock.  It stops at almost every ferry stop except Rumelian Fortress, which makes it a lot slower, but gives the the ability to create your own Hop-on, Hop-off tour..  There is tourist no narration.  This route is marked in Blue on our map.

istanbul bosphorus river sunset cruise
4. Sunset Night Cruise (Mehtap Gezi):
Out of all of the Bosphorus Strait River Cruises in Istanbul it is always extremely hard for use to choose between the Full Tour and the Sunset Night Cruise.  We love to explore on the Full Tour, but the beauty of the sunset and moonlight on the night tour is awesome.  From July through August Şehir Hatlari offers a Moon Light version of the Full Bosphours Cruise tour for just 20TL.  The tour leaves Eminönü around 7pm, gets to Anadolu Kavağı around 8:30pm for a 2 hour layover, and gets back to Eminönü at Midnight.  Tour does not include dinner but you’ll have plenty of time to eat during the layover.  Cost: 20 TL ($10) Round Trip.  Time: 5 hours round trip with layover, alternatives below are shorter.

Alternative Sunset Cruise Option: Turyol Ferry Service (website) does an evening version of the Short Cruise Loop without narration in just 90 minutes for 12 TL ($6). In peak season they leave at 7, 8, & 9pm but you have to check the schedule in person.  Alternative Sunset Cruise Option 2: At the docks you will also find various companies offering 3 hour dinner cruises complete with Turkish meals and belly dancers for around $100 a person. These tours are fun if you don’t mind the extra cost.

The Bosphorus Strait Tour Sights:

istanbul bosphorus river tour, cruise map, galata bridge

1. Galata Bridge (Galata Koprusu): The energetic Galata Bridge is the perfect segway connecting Istanbul’s historic Old Town and modern New Town to the North.  The two-tiered bridge is always peppered with pedestrians and forever full of life. Local fisherman line the rails of the upper level trying to snag a bit with their poles and countless restaurants and shops await your business down below.  We love the atmosphere of the areas surround the bridge no matter what time of day and the water side restaurants on Galata’s lower level are charming after dark.

In the days of Constantinople, the Byzantines strung a giant liftable chain across the Golden Horn roughly where the Galata Bridge is today to stop unwanted ships from coming in from the Bosporus River.  Many groups tried to bust through the  chain but it wasn’t until the Ottoman conquest of 1453 that anyone did.  The Ottomans debated building a permanent bridge where the chain had been many times but for hundreds of years it never got to be anything more then a group of barges tied together.  Leonardo da Vinci was even brought to Istanbul and submitted a potential bridge design which was turned down by the Sultan.  When the Sultan asked Michelangelo to submit a plan after that he said no.  Finally in the mid-1800’s the Ottomans started building a series of wooden bridges up and down the Golden Horn, some even had varying levels of tolls.  In the early 2000’s they replaced the last of the wooden bridges with concrete ones including the current Galata Bridge. North of Galata is our New Town Walking Tour and South is our Grand Bazaars Walking Tour.

istanbul bosphorus river tour, cruise map, maidens tower


2. Maiden’s Tower (Kiz Kulesi):
Greek Generals from Athens built were the first to build on the small island with a fort in 411BC.   The first tower was built much later in 1190AD by Byzantine Emperor Comnenos called Arcla, meaning small castle.   In 1453AD Ottoman Sultan Mehmet placed cannons here and the tower was renamed Maiden’s Tower after a series of local legends explained below.   Since the 1700s, the tower has been used as a lighthouse, jail, and place to quarantine people with cholera.

istanbul bosphorus river tour, cruise map, maidens tower

Maiden Legend 1: The first legend comes from the ancient story of Leanders Tower from 500BC.  It’s kind of a weird association since Dardanelles or Hellespont on the other side of the Sea of Marmara, has actually been called Leanders Tower since the 1600s, but the story is good.  In the legend Hero, a priestess sworn to Aphrodite, the Greek goddess of love, was imprisoned here to ensure her sanctity.  A man named Leander somehow encountered Hero perhaps by passing in a boat, and fell fatally in love.  Swimming to the tower every night, Leander gradually won her love.  Hero lit a torch at the top of her tower every night to guide Leanders long swim.  One stormy night, the wind blew out the torch, Leander lost his way and exhausted, he perished beneath the waves.  His body washed upon the rocks of this island, and Hero, seeing this was distraught and heartbroken so much, so that she leap from the tower to her death, thus ensuring the immortality of their love.

istanbul bosphorus river tour, cruise map, maidens tower

Maiden Legend 2: A sultan had a much beloved daughter. One day, an oracle prophesied that she would be stung to death by a venomous snake bite on her 18th birthday. The sultan, in an effort to overcome her fate, wanted to keep the princess away from land and snakes.  He had the tower built in the middle of the Bosphorus River to protect his daughter until after her 18th birthday.  The princess was placed in the tower, where she was frequently visited only by her father. On the daughter’s 18th birthday, the sultan brought her a basket of exotic fruit as a birthday gift, delighted that he was able to prevent the prophecy.  As she reached into the basket, however, an Asp snake that was hiding in the fruit bit her and the princess died in her father’s arms, just as the oracle had predicted.  Hence the name Maiden’s Tower.

Getting To Maiden’s Tower: You’ll see Maidens Tower off to the East near the Asian side of Istanbul once you right the Bosphorus, but none of the Full Cruise options above will get you right up to the Tower.  You’ll need to take the Ferry to Üsküdar to get close which only takes 10 minutes and leaves every 15-20 minutes daily 6am-10pm.  If you happen to be on an IBO Ferry Tour on a Monday, Wednesday, or Thursday they sub in a stop at the Tower in place of other main sights that are closed.


3. Dolmabahçe Palace:
In the late 1800’s a series of lazy and incompetent Sultans had started to push the Ottoman Empire into decline so Sultan Abdülmecid I, the Empire’s 31st Sultan, decided to build Dolmabahçe Palace in an effort to get the Empire’s mojo back. The Sultan thought the prior Palace was too oriental and felt they needed one more in the image of the Rocco palaces of Austria and France. It took the Sultan from 1843 to 1853 to complete, but when he was finished the result was a Palace any royal monarch would be happy to call home.

istanbul bosphorus river tour, cruise map, dolambahce palace

In all the Palace covers 11.2 acres, has 285 rooms, 46 halls, 6 baths (hamams) and 68 toilets.  Although cool, it was kind of a weird place to build a palace as it was largely part of a bay on the river which needed to be filled in, but that’s how the Palace got its name Dolmabahçe meaning Filled Up Garden.  Dolmabahçe became the 3rd official governing Palace of the Ottomans with the 1st at today’s Istanbul University, the 2nd at Topkapi Palace, and from 1887 to 1909 there was even a briefly a 4th at the neighboring Yıldız Palace just to the North. In the end, the building of Dolmabahçe Palace didn’t help the fate of the Empire as only 6 Sultan’s got to live here before the Ottomans were thrown out of power in 1922. When the modern government of Turkey took over 1924 they quickly turned Dolmabahçe Palace into a museum.

istanbul bosphorus river tour, cruise map, dolambahce palace

Guided Tour: The only way to enter the Palace Grounds is to buy tickets for a guided tour. Guided tours of the Palace interior start about every 25 minutes in both Turkish and English and visit both the Selamlık and the Harem. You’re free to roam the ground of your tour until 5pm.  Tour Hours:  Tuesday, Wednesday, & Friday-Sunday 9am-4pm, closes at 3pm from late October-March; Closed Mondays & Thursdays.  Don’t chance it by getting there late as their is a 3,000 visitor a day limit which sells out before close in the busy season.  Tour Cost: Selamlık Tour is 30TL, Harem Tour is 20TL, Combo ticket for both is 40TL.  We suggest only getting the Selamlık ticket.  Getting Here: Most of the ferries stop directly here or nearby as does Tram #2.  In reality because it is only open from 9am-4pm it can be tough to tour the inside while on a River cruise.  To make it work, you either need to pick a half day tour and see it on your way home or do the Preme Ferry Tour which leaves from here at 11:15 giving to time to check out the Palace before your cruise. Dolmabahçe is also in our New Town Walking TourBrochure: Here

istanbul bosphorus river tour, cruise map, Ortakoy Mosque


4. Ortaköy Mosque:
Built in 1854, Ortakoy Mosque is a very pretty, but quaint riverside mosque.  It may be small but pictures with river and Bosphorus Bridge in the background are cool, especially in the evening.  You may have noticed a large Palace looking building just South of the Mosque, it’s the former Çırağan Palace.  The Palace was made for event hosting and they went all out spending a whopping 4 million gold pieces on it.  Unfortunately it started sliding into ruins in the early 1900’s but has been bought and it now all fixed up and serving as a 5-star hotel.  Getting Here: The IBO Ferry Tour stops here for almost 30 minutes.  The stop is also serviced by the Bogaz Hatti Passenger Ferry as well as both bus 25 and 40.

istanbul bosphorus river tour, cruise map, bridge


5. Bosphorus Bridge:
Connecting the European and Asian sides of Istanbul, the Bosphorus Bridge was the World’s 1st Trans-Continental bridge when it opened in 1973. With a clearance above the river of 210 feet and length of almost a mile, the impressive bridge was also the World’s 4th largest suspension bridge when it was completed.  You can definitely tell it is a huge bridge from the shore, but once you pass underneath it is when it really wows you.  The perspective as you approach and glide under the bridge on your ferry is unmatched.  Most of the Bosphorus Strait River Cruises in Istanbul at least go to the bridge and all of the longer tours go past it.


6. Beylerbeyi Palace:
This beautiful white marble palace, with tons of magnolia trees, served as a Summer house for Sultans and a guest house for foreign dignitaries. Many guests stayed there like Franz Joseph, Emperor of Austro-Hungary (1869); Eugenie, Empress of France (1869); King of Montenegro (1874) and German Emperor Wilhelm II.  Beylerbeyi Palace was built by Sultan Mahmut II, and is where his son Sultan Abdülmecit personally tested Samuel Morse’s new invention, the telegraph, in 1847.  Sultan Abdülmecit liked it so much that he immediately issued a royal patent to Morse, considered the world’s first patent for the telegraph. Sultan Abdülhamid II spent his last six years in Beylerbeyi Palace after he’d dethroned and died there in 1918.

istanbul bosphorus river tour, cruise map, Beylerbeyi Palace

The interior design of the palace both in Western and Eastern style has some similarities with ancient Turkish houses. There are three stories including basement, 24 rooms and 6 halls.  The floors are covered with Egyptian straw mat. Carpets are mostly from Hereke, Turkey; chandeliers are of French Baccarat crystals; clocks are made in England, France and Golden Horn Shipyard in İstanbul; vases are from China, Japan, France, Germany and Yıldız, Turkey.  Besides them there are also other unique works of arts adorning rooms and halls.  Our favorite facet is the underground escape tunnel added by Sultan Mahmud II between 1829 and 1832.

istanbul bosphorus river tour, cruise map, Beylerbeyi Palace

Hours: Friday-Sunday & Tuesday-Wednesday 8:30am-4:30pm; open until 5pm in the Summer; Closed on Mondays & Thursdays.  Cost: 20 TL.  Getting Here: The Palace is located kind of by itself on the Asian side of the river and no buses directly cross the Bosphorus Bridge.  From Ortaköy Mosque you can take the river crossing Boğaz Hatti passenger ferry, but stay on until two stops to the the Beylerbeyı Dock which is very close.  The best option to see the Palace without doing a private boat tour is to use the Pereme Hop-on, Hop-off boat explained above which can give you an hour to explore.  The entire Asia bank is also covered by routes for Bus 15 which is slow on the weekends.  Brochure: Here.


7. Küçüksu Pavilion:
Also known as the Göksu Pavilion, the Küçüksu Pavilion was first built in 1751 as a getaway for the Sultan to hunt and target practice. The original pavilion was made of timber and replaced with current pavilion in 1856 which was a full-on Summer retreat. It’s a very compact pavilion with three stories including the basemen that was built in an area of 49×88 feet. There was a pantry, kitchen and servants’ quarters in the basement; other floors were designed in traditional Turkish house plan with four rooms surrounding a hall in the middle.

istanbul bosphorus river tour, cruise map, Kucuksu Pavilion

Western designs were used on the embossed sea front facade, the fountain pool, and the beautiful staircases. The old hunting lodge is a rich art museum with ceilings decorated with plaster reliefs and engravings; fireplaces made of various colored, precious Italian marble and elegant parquet floors with different patterns in each room.  Brochure: HereGetting Here:  While the Boğaz Hatti passenger ferry stops nearby the best way to see this Palace is with either the long or short cruise offered by IBO Cruises.  Both of their options stop right outside and give you a full hour to explore before you head out.  Also covered by routes for Bus 15.

istanbul bosphorus river tour, cruise map, Kucuksu Pavilion


8. Anatolian Fortress (Anadoluhisarı):
This 7 acre fortress was built by Sultan Beyazid I in 1395 as the Ottoman’s front line military outpost as they slowly crept closer to Byzantine Constantinople. The main storage building squarely sticks up above the neighboring buildings, but look close and you’ll see a stout fortress wall with numerous round towers throughout it. Unlike other outposts, Anatolian was built right by the water instead of being up on a hill. Although building close to the water opened them up for attack, it also gave the Ottomans quick access to the Bosphorus River at its narrowest point. The fortress held true as the Ottomans grew their strength over 30 years before their final assault on Constantinople.  Today the fortress ruins are really neat to visit are and entire neighborhood has tightly grown around the fortress and in some places incorporated it.  Just a great, unique mix of old and new.  Getting Here:  The Boğaz Hatti passenger ferry which stops out front is the best way to see this fortress. Also covered by routes for Bus 15.

istanbul bosphorus river tour, cruise map, Anatolian Fortress


9. Rumelian Fortress (Rumelihisarı):
To completely pinch the Bosphorus at its narrowest point, the Ottomans choose to build Rumelian Fortress on the European side of the river directly across from the Anatolian Fortress.  Rumeli, which is considered one of the largest and strongest Medieval fortresses, was completed in the amazingly short time of just 4 months in 1452.  Controlling both sides of the rivers was genius as it helped to block off support and supplies from the Black Sea to the North.  If you think they built it quick, the new fortress helped the Ottomans conquer Constantinople so fast that they only occupied Rumelian for a little over a month before the City was theirs.

istanbul bosphorus river tour, cruise map, Rumelian Fortress

Hours: Thursday-Tuesday 9:30am-4:30pm, closed on Wednesdays.  Getting Here: The best way to see this Palace up close is with either the long or short cruise offered by IBO Cruises.  Both of their options stop right outside and give you a full hour to explore before you head out.  Also covered by routes for Bus 25-E which is slow on the weekends but runs along the River all the way from Sarıyer in the North down to Dolmabahçe Palace.


10. Bosforo Village:
Bosforo is the first village with a lot of colorful homes clinging to the water.  The wooden mansions, called Yali were built as Summer houses along the river by Istanbul’s wealthy residents in the 1700 & 1800s.  In total there are 680 of the Yali with most of them condensed in the Northern most villages.  The coolest of these homes in Bosforo is called the Sait Malim Pasa Mansion and located right where our map marker.

istanbul bosphorus river tour, cruise map, Anadolu Kavagi Village


11. Sarıyer Village:
Yeni Mahalle Street which runs along the water is filled with tightly packed and brightly colored European-style Yali homes. Sariyer is a good jump off point to hut up the larger Northern beaches with Bus 151.  You can also hop on bus 25-E to visit Rumelian Fortress up close if you are on a Ferry that doesn’t stop there directly.  Getting Here: Serviced by both Şehir Hatlari ferry lines and connected to most of the West bank by Bus 25.

istanbul bosphorus river tour, cruise map, Yoros Fortress


12. Anadolu Kavagi Village & Yoros Fortress
: Sitting high above Anadolu Kavağı with views of not just the Bosphorus, but also the Black Sea to the North, Yoros was much more of a citadel than a mere Fortress.  The Byzantines saw the advantage of building here and quickly built on the same place where Phoenician and Greek ruins from hundreds of years B.C. and being excavated today.  The Fortress served the Byzantines well for 1,000 year until they saw their control of it go back and forth with the Ottomans during the 1300’s.  In 1391 the the Byzantines were finally driven out of Yoros Fortress for good which gave the Ottomans a starting point to build Anatolian to the South.  Although this move was the start to the Ottomans overtaking the Byzantines, they also had to deal with the Genoese who had a strong presence in what is now New Town Istanbul.  As the Ottoman’s advanced on Constantinople, the Genoese sacked Yoros Fortress in 1419 and weren’t driven back out by the Ottmans for 40 years. By the time the Ottoman Empire fell over 400 years later, Yoros Fortress was barely being used.

istanbul bosphorus river tour, cruise map, Yoros Fortress views

Today, the Fortress is technically owned by the Turkish Military and closed to visitors, but is not monitored much.  Most tourist will be able to walk anywhere there aren’t archaeological excavations going on.  Even if you climb up the the Fortress and it’s closed the outer wall, main gate, and views of the Black Sea make the hike worth it for sure.  If you decide to bypass the hike to just stroll through Anadolu Kavağı instead you will be pleasantly surprised.  The city is full of cute two story houses with cobblestone streets, and fish restaurants giving you great options of either lunch or dinner.


13. Poyrazköy Village & Beach:
fishing village which is the first in from the Black Sea, has a small sandy beach which is the best directly on the Bosphorus Straight.  Not all of the Bosphorus Strait River Cruises in Istanbul go to the beach, so make sure to consult our map above if this if you want to actually get off here instead of just floating past.

istanbul bosphorus river tour, cruise map, Poyrazköy Village, black seaBeach


14. The Black Sea:
The Black Sea, which is visible from Yoros Fortress lies just North of Istanbul and has been very important to the city over time.  In addition to the Aegean and Mediterranean Seas the the South, the Black Sea was a huge avenue for both growth and advancement.  Thrown in that Istanbul was in the straight that connected them all and you can see why it is still a strong 15 million person melting pot of a city today.  The Black Sea not only gave Istanbul trade access to Russia but also to many other major cities in modern day Romania, Bulgaria, Turkey and more.  It’s safe to say that the city that controlled the traded controlled the power.

Map

http://sehirhatlari.com.tr/harita/index.html

Bus Route Map & Planner

http://harita.iett.gov.tr/