In 1946, the communist regime erected on the square a monument to Soviet soldiers liberating Hungary. Soon another monument appeared, which fakely expressed the grateful from the Hungarian people to the great Stalin. It was the monument to Stalin that Hungarians destroyed during the uprising against the Communists in 1956. The memorial to the Soviet soldiers was repeatedly desecrated, and a policeman was always on duty near it. An interesting fact: behind the monument, you can see a large outlet of the ventilation pipe. This pipe is the ventilation system of the underground bunker, which the Communists began to build in 1952. The construction was completed in 1963. Three years later, the shelter was connected to the Budapest metro. An air filtration system can produce four thousand cubic meters of clean air per hour. This amount is equivalent to one hundred and twenty sea containers.