The city is built on the location of the Latin city of
Cabum. Documents from 12th century name Rocca di Papa as
Castrum Rocce de Papa ("Rock of the Pope Castle"), because
Pope Eugene III lived there. In 1541,
Pier Luigi Farnese and French troops destroyed the castle. In 1855, the town proclaimed the "Rocca di Papa Republic" against prince Colonna and the
Papal States. In 1889, the "Royal Geodynamic Observatory" was built on the top of Rocca di Papa, near the little Church of the Crucified. Between 1922 and 1935, the scientist
Guglielmo Marconi carried out several experiments from this building in radio-transmission, wireless transmission and broadcasting. In 1944, during
World War II, Rocca di Papa was bombed, destroying the town centre. 34 people died in that airstrike, and 35 more died in a second one on 25 May. The city was liberated from the
Nazi German occupation on 4 June 1944 by the
85th Infantry Division, of the
United States Army. In June 2019, an accidental explosion at the town hall building killed Mayor
Emanuele Crestini and another man, while several others were injured. == Main sights ==