Budapest is well served by its underground railway system. The Millennium Underground Railway, or Metro 1, is its oldest line, and the second-oldest underground railway in the world (after London). So getting around is easy, and there is lots to explore. Visit the grand Heroes' Square with the Tomb of the Unknown Soldier, or make your way to the Hungarian Parliament Building, which is especially beautiful by night. Numerous parks, many with playgrounds for children, are great to get away from the hustle and bustle of the city. Several islands in the Danube River also offer opportunities for sports and relaxation. With great train links to Budapest from all over Europe, this is a great city for a weekend getaway or a longer holiday.