The exhibition is located in the top floor of the tower of the St. Nicholas Bell Tower on the Malostranské náměstí. Visitors can visit the place where, from the beginning of the 1950s until the fall of the communist regime, was an observatory of the State Security, the secret political police, which was one of the main pillars of the communist regime in the Czech Republic. From here, its officers continuously monitored the movements around the Western embassies located in the vicinity of the tower.