The colossal equestrian statue of the one-eyed General Zizka reminds us that here, in 1420, the destiny of Bohemia, and the Empire, was shaken. With lesser numbers, the Hussite troops, up against such solid defences, fell at the hands of the Imperial and Papal cavalry intent on stamping out heresy. The hill eventually became a working-class suburb - ''Red Zizkov'' supplied battallions to the triumphant Communists - and a favourite spot for Prague's Roms.