The Ottoman Dynasty extended over three continents, surviving 600 years from the Middle Ages to the beginning of the 20th century. 24 of its 36 Sultans ruled the Empire from Topkapi Palace in Istanbul, for a period of 400 years. The royal residence, which has witnessed moments of great joy and sorrow, became a museum after the founding of the Turkish Republic in 1923 by Kemal Ataturk. Until it opened its doors to visitors from all over the world, the Topkapi Palace had always been a mysterious, shuttered world. The "Topkapi Palace" series represents the widest-ranging project of its kind ever to be taken. It was in 1990 that all the doors of the Topkapi Palace were opened to a film crew for the first time. Their lights probed parts of the palace still closed to visitors and, indeed, into places that had never seen the daylight.