The Monument to the Unknown Hero ( / Spomenik Neznanom junaku) is a World War I memorial located atop Mount Avala, south-east of Belgrade, Serbia, and designed by the sculptor Ivan Meštrović. Memorial was built in 1934-1938 on the place where an unknown Serbian World War I soldier was buried. It is similar to many other tombs of the unknown soldier built by the allies after the war. The Žrnov fortress was previously located on the same place.