Praguecity of many spires

Prague’s top-rated tourist attraction clocks in as the largest ancient castle in the world, according to Guinness World Records, and covers an 18-acre hilltop overlooking Malá Strana with buildings constructed over more than a thousand years (incorporating architectural styles from the Romanesque to the postmodern). Despite the grandeur and the history, Prague Castle maintains its long-term role as an administrative center, hosting the office of the country’s president and other government departments. Because they are public buildings, entry to the castle grounds is free, though tickets are required for many of the most interesting tourist sites, including the Castle Picture Gallery, the Old Royal Palace, St. George’s Basilica and the Rosenberg Palace. Whatever you choose to see, give yourself at least a few hours: You could spend days up here and never come close to seeing everything.