Yedikule Fortress is a fortified historic structure located in the Yedikule neighbourhood of Fatih, in Istanbul, Turkey.
Built in 1458 on the commission of Ottoman Sultan Mehmed II, the seven-tower complex was created by adding three new towers and fully enclosing a section of the ancient Walls of Constantinople, including the two twin towers that originally constituted the triumphal Golden Gate built by Roman Emperors Theodosius I and Theodosius II.
The fortress came to be known as the home of a formidable royal dungeon that housed notable figures throughout its history, and the associated intrigue captured the public's imagination over the centuries in various legends, stories, and the arts.
Wikipedia https://en.wikipedia.org/wiki/Yedikule_Fortress
Address Yedikule Mh. 34107 Fatih, Istanbul,Turkey
Coordinates 40°59'37.705" N 28°55'22.302" E