Bois de Vincennes, Paris

The Bois de Vincennes is Paris's largest public green space, covering 995 hectares on the eastern edge of the city — roughly three times the size of New York's Central Park. Originally a royal hunting ground used by French kings from the 12th century, it was transformed into a public park by Napoleon III and Baron Haussmann between 1855 and 1866. The park contains four lakes, dense woodland, and several major attractions within its boundaries: the medieval Château de Vincennes with Europe's tallest surviving keep, the Parc Floral botanical garden, and the renovated Paris Zoo with five continental biozones.