More than half of humanity now lives in cities. Meanwhile, the flora and fauna are investing more and more urban areas. With a surprising result: the relationship between animals and humans have never been as numerous, dense and rich! For the first time, exploration of biodiversity is at the heart of the city and human activities. And for the first time, the city is accounted for through nature that deploys it. In Naturopolis, actors, thinkers, scientists, dreamers and builders of tomorrow invite us to explore the natural wealth unknown four megacities: New York, Paris, Rio de Janeiro and Tokyo.