Rumeili Hisari Fortress (RumeIiHisari) Introduction: It is located on a hill on the European side of the narrowest point of the Bosphorus in the Salyer District of Istanbul, Turkey. It is one of the most beautiful masterpieces of military buildings in the world. It is also called the European Fortress. It was built in only 4 months when the Sudanese dynasty conquered Istanbul (1452). Covering an area of ​​about 250M*125M, it is mainly composed of three tower-shaped fortresses connected together by city walls. The diameter of the three towers is 23~27M and the height is 21~35M. Except for one which is a 12-prism, the others are all cylindrical. Between the three main towers there are many smaller towers similar in shape to the main tower.