Another stunning example is L'Oasis d'Aboukir, aka Hymne à la Biodiversité (Ode to Biodiversity), with some 7600 plants from 237 different species growing on a 25m-high facade in the 2e arrondissement (city district). Murs végétaux (vertical 'living wall' gardens) are greenifying the exteriors of buildings such as the Musée du Quai Branly. Ground-breaking green spaces in recent decades have included the Parc André Citroën, on the site of a former Citroën car manufacturing plant (the park's aerial sightseeing balloon, the Ballon de Paris, monitors air quality, changing colour accordingly), and the Promenade Plantée, the world's first-ever elevated park, atop a disused railway viaduct (inspiring New York's High Line).
Ballon de Paris floats above the Parc André Citroën, a new green space in Paris © Catherine Le Nevez / Lonely Planet Parks, gardens and public spaces
