The iconic André Citroën car manufacturing plant, founded in the 15e district of Paris in 1915, closed its doors in the 1970s. Today, this 14-hectare urban park has replaced the now-vacated site, offering its visitors a forward-thinking green space. Its central lawn is surrounded by greenhouses, dancing fountains, an elevated reflecting pool and smaller gardens that are each themed around movement and the six senses. Visitors to this park can also take to the skies in the helium-filled sightseeing balloon Ballon de Paris, although it's recommended to check the seasonal hours of operation at the entrances.