Hambach Forest Treehouse, North Rhine-Westphalia, Germany

The industrial complex in North Rhine-Westphalia is giant, comprising multiple coal mines and some of Europe’s biggest carbon emitters. Together, nearby coal plants Neurath and Niederaußem emit as much carbon as entire countries.

The Hambach lignite mine is the largest open-cast mine in Western Europe, with a surface area of around 80km². At its deepest point it has been excavated to a depth of 0.5km.