The military museum and culture center was renovated and reopened at its present building in 1993 with a very successful and contemporary exhibition concept. Today in 22 rooms about nine thousand pieces from the Ottoman era through World War I are exhibited, out of a total collection of fifty thousand objects. It holds striking historical treasures such as the chain that the Byzantines stretched across the mouth of the Golden Horn to keep out the Sultan's navy in 1453 during the siege of Constantinople. The east wing of the museum is used for temporary exhibitions, meetings and similar activities. On the ground floor, the display of bows and arrows in the first room is followed by sections containing the weapons and other regalia of the cavalry, curved daggers and lancets carried by foot soldiers in the 15th century, 17th century copper head armor for horses and Ottoman shields carried by the janissaries, and sections devoted to Selim I, Mehmet the Conqueror, the conquest of Istanbul, weaponry from the early Islamic, Iranian, Caucasian, European and Turkish periods. This floor also houses a unique collection of helmets and armor, as well as the sections allocated to firearms and great field tents used by sultans on their campaigns. On the upper floor there are rooms where objects from World War I, the Battle of Gallipoli, and the Turkish War of Independence, and uniforms from more recent times are displayed. There is also a room which is dedicated to Atatürk, who studied in the building when it was a military academy between 1899-1905.