The idea has a name and a birth year. In 1998, conservation biologists Michael Soulé and Reed Noss coined the term “rewilding” around what they called the three Cs: protect large core wild areas, connect them with corridors, and bring back the carnivores that keep the whole system in balance. Three years earlier, in 1995, the theory had already had its proof of concept. Wolves were reintroduced to Yellowstone National Park after being wiped out there for seventy years. Elk stopped overgrazing the riverbanks, willow and aspen came back, beavers returned, and the rivers themselves changed course. One species, brought back, reshaped an entire landscape.

Europe took the idea and ran with it at a scale nobody expected. Rewilding Europe, founded in 2011, now coordinates large rewilding landscapes across the continent. The best-known example is Knepp Estate in southern England, an unprofitable, chemically farmed property that stopped intensive farming in the early 2000s and let the land go. Two decades on, it's become a stronghold for critically endangered nightingales and turtle doves, home to the largest population of purple emperor butterflies in the country, and now runs safari tours and stays that help fund the whole project. From one valley in Wyoming to farms across England, Portugal and Spain, the same idea keeps proving itself: land recovers fast once you get out of its way.