A radiation protection engineer walks in front of the sarcophagus covering the destroyed fourth reactor under the New Safe Confinement (NSC), at the Chornobyl Nuclear Power Plant, amid the Russian invasion of Ukraine. An uncontrolled collapse of the internal radiation shell at the defunct Chornobyl nuclear power station in Ukraine could increase the risk of radioactivity release in the environment, Greenpeace has warned. (AFP via Getty Images)