The city is like a living organism. Healthy and in perfect balance, it can make its inhabitants happy, people as well as animals and plants. If it gets out of balance, it becomes ill and with it all the creatures that live in it. It is a valuable habitat for animals such as hedgehogs, rhinoceros beetles and swallowtails. But cities are under pressure. Growing population numbers are leading to the loss of green spaces and increased soil sealing. This is threatening the health of cities. How can we keep them healthy or even make them healthier?