Yedikule Fortress

Yedikule Fortress (Yedikule Hisarı or Yedikule Zindanları, meaning "Fortress of the Seven Towers") 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 twin towers that originally constituted the triumphal Golden Gate (Altınkapı) 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.

Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).