Anadolu Hisari (Anatolian Fortress)
A 14th century castle from the Ottoman’s first attempt to capture Istanbul, Anatolian Fortress is located on the Asian shore of the city at the narrowest point of the Bosphorus Strait. Sultan Yildirim Bayezit built this fortress in 1395 on the ruins of an old temple devoted to Zeus.
The fortress is much smaller (7.000 m2 – 1,7 acres) in size when comparing it with Rumelihisari on the European side of Istanbul. Its towers are about 25 meters (82 feet) high with 2-5 meters (7-16 feet) tickness. The fortress was also named “Güzelce Hisar” in some historical documents. Today, Anadolu Hisari is an open air museum but only outer walls can be visited, and the road passes just through it.
Rumelihisari (Rumeli Fortress)
Rumeli fortress was built by the sultan Mehmet the Conqueror in four months only and directly opposite to Anadoluhisari in 1452 in readiness for the final attack on Constantinople, which led to the downfall of the Byzantine Empire. The fortress is situated at the narrowest section of the Bosphorus Strait (about 600 meters – 1970 feet). It occupies an area of 60.000 m2 (16 acres), had 4 main and 1 smaller gate, and 3 large and 1 smaller tower.
From a small mosque inside, only its minaret survived. Rumelihisar suffered from big earthquakes but was always restored, final restoration was done in 1953 and opened as a museum. Today, the fortress is open to the general public as an open-air museum and hosts many concerts and dramatic performances in its amphitheater usually during the summer season.
Yedikule Hisari (Seven Towers dungeons)
As its name says in Turkish, Yedikule is a seven towered fortress which was built next to the city wall near the Byzantine Imperial Gate (Golden Gate or Porta Aurea) during the reign of Sultan Fatih Mehmet to safeguard the treasury. Over the sultan Murat III’s reign, the treasury was relocated to the Topkapi Palace and Yedikule started to be used as a dungeon.
The place of imprisonment of many foreign ambassadors and Ottoman statesman, in addition to a place of execution for some, the fortress was last used as a prison in 1831. It than became a dwelling for the lions of Topkapi Palace, and later a gunpowder manufacturing place. Today, the fortress is a museum which is also hosting open air concerts in the inner courtyard during the summer season.
Sehir Surlari (City Walls)
Since the times of old Byzantium, a fortified city wall starting from the Golden Horn surrounded the city and reached the Sea of Marmara. But the land walls that we see today in Istanbul were built throughout the Byzantine period. First, Theodosius started to build a city wall in the 5th century AD than it was enlarged in the 6th century during the reign of Justinian as a result of expansion of Constantinople. These walls were sufficiently strong to stop enemy sieges such as Arab and Persian attacks in the 7th and 8th centuries but it couldn’t stop the Ottoman army during the Conquest of Constantinople in the 15th century.
Throughout the Ottoman period, the wall was useless because Istanbul was in the center of a huge Empire thus it was impossible for the enemy to capture all these lands until they could reach the city. Therefore the land walls were used as construction material and mostly destroyed due to the earthquakes. Today, some sections of the wall are being restored by the local municipality to remember its glorious times.
The Byzantine wall was split into 3 sections: Marmara Sea walls, Golden Horn walls, and Land walls. The walls had over 300 big towers (20-25 meters – 65-82 feet high) for its defense and about 55 gates giving entry to the city; 19 of them were at the Sea wall, 25 at the Golden Horn wall, and 11 at the Land wall. The city wall was about 22 kilometers in total, 9-12 meters (30-40 feet) high with 2-5 meters (7-16 feet) of tickness. There was clearly a water canal in front of the land walls to stop any possible climb with ladders or digging a tunnel underneath.