The nuclear bunker beneath Malé náměstí was engineered to shelter 5,000 civilians for 72 hours during a nuclear strike that Prague's civil defense planners treated as inevitable. Construction began in 1953, eight years after Soviet troops liberated the city and three years into Czechoslovakia's hardline Stalinist phase. The shelter's ventilation system could filter radioactive particles at a rate of 12,000 cubic metres per hour. Its walls, reinforced with steel rebar salvaged from dismantled tram lines, were designed to withstand a 20-kiloton blast within a two-kilometre radius. By 1989, when the Velvet Revolution ended Communist rule, the bunker had never been used. Above ground, the streets traversed by a Prague communism walking tour carry the visible architecture of socialist transformation. Wenceslas Square, where Jan Palach set himself alight in January 1969 to protest the Soviet invasion, remains lined with functionalist facades erected during the normalization period that followed the Prague Spring. The buildings are clad in prefabricated concrete panels stamped with geometric reliefs, a construction method imported from Soviet industrial centres. Many still bear the faint outlines of removed hammer-and-sickle emblems. The Czechoslovak Socialist Republic erected 140,000 panel apartments in Prague between 1960 and 1989, housing nearly a third of the city's population. The walking route passes former state enterprises that once operated under centralized five-year plans: the Máj department store, a rare example of Brussels-style modernism approved by Party authorities in 1975, and the Kotva building, whose hexagonal modules were cast in a factory near Plzeň. The tour descends into the bunker from a concealed entrance in Staré Město, negotiating 84 steps to reach the main corridor 10 metres below street level. Original decontamination chambers, Geiger counters, and rotary dial telephones connected to the civil defense network remain in place. The bunker's emergency generator, a Soviet-manufactured diesel unit capable of powering the shelter for 96 hours, sits in a ventilated alcove behind a steel hatch. Guides reference declassified Ministry of Interior documents that outlined evacuation protocols for Party officials and essential workers, a hierarchy that reserved upper bunker tiers for nomenklatura families. The Cold War bunker tour concludes in the main dormitory, where steel-frame bunk beds are stacked three high beneath peeling propaganda murals depicting heroic workers defending socialism.