A vast space is needed for these aircraft, vintage cars, an 80-year-old snowmobile, a World War II mini-submarine, 19th-century fire engines and a Dubrovnik tram from 1912. There's also a small planetarium, flanked by a life-size model of an unmanned Soviet moon-roving vehicle, and a similarly true-to-life copy of the American Mercury programme space capsules of the early Sixties. The section dedicated to Nikola Tesla illustrates just how advanced this turn-of-the-century pioneer of electricity generation and radio transmission actually was. Daily demonstrations in his laboratory involve a short lecture during which some of his inventions are put through their paces. There are also tours of the museum's mine and, on Sundays at 9.30am, a 1924 tram takes you to Maksimir and back, for free.