Norway has just authorised commercial deep-sea mining on its seabed, which is rich in rare and precious metals. This announcement has whetted the appetite of mining companies, which are developing robots and drones to collect the rocks, located at a depth of 3,000 metres. Billions of euros are at stake in the exploitation of these so-called critical minerals, which are essential for building electric vehicle batteries and solar panels. But deep-sea mining could prove devastating for ecosystems.