The Skull Tower (Serbian: Ćele Kula, Turkish: Kelle Kulesi) is a monument to 19th century Serbian rebels who fought for independence against the Muslim Ottoman Empire (1804-1813). It is situated in Niš, Serbia, on the old Constantinople Road leading to Sofia.
After the retreat of the Serbian rebel army in the 1809 Battle of Čegar, the Turkish commander of Niš, Hursid Pasha, by order of Ottoman Sultan Mahmud II, ordered that the heads of the killed Serbs to be mounted on a tower to serve as a warning to whoever opposed the Ottoman Empire.
Rectangular in its base, 3 meters high, Skull Tower was built out of 952 skulls, with the skull of Sinđelić, the Serbian commander, placed at the top. The scalps from the skulls were stuffed with cotton and sent to Constantinople (modern Istanbul in Turkey) as proof for Sultan Mahmud II.
The tower stood in the open air until the liberation of Niš in 1878, and, in 1892, a chapel was built to enclose what was left of the tower. Skull Tower was declared Monument of Culture of Exceptional Importance in 1979, and it is protected by the Republic of Serbia.