PETRIN HILL overlooks the city of Prague. You arrive there via a steep funicular railway that starts at Ujezd and if you take the route through the ornate gardens, you find one of the monuments to a past political regime, the grey and imposing Strahov stadium. Strahov is a crumbling reminder of how Soviet-style governments liked to build vast socialist superbowls that held huge numbers of people. Behind the “iron curtain”, such stadiums existed to stage events that underlined the strength, good order and health of the nation. In the case of Strahov, it was built primarily for physical exercise, Czechoslavakia’s own brand of nationalist gymnastics known as Sokol. This started many years before the second world war, but the emphasis placed on it…