Spreading across Paris's eastern edge like a green escape hatch, the Bois de Vincennes holds four lakes, winding trails, and enough open space to forget you're still in the city. Napoleon III opened these grounds for working-class Parisians in 1860, and the spirit of accessible leisure remains: cycle between Lac Daumesnil and Lac des Minimes, drift across the water in a rowboat, or claim a patch of grass for an afternoon picnic.