Europe's biggest nuclear power plant has been shelled by Russian forces in Ukraine.
The attack caused a fire to break out, which has since been extinguished.
Ukraine says Russian troops are now in control of the plant.
The International Atomic Energy Agency says radiation levels at Zaporizhzhia ((pron: zaper-ree-sha)) do not appear to have changed.
But Ukrainian officials say there's a "real threat of nuclear danger" and if it blows up, it could be 10 times larger than Chernobyl.
Professor M-V Ramana, an expert in nuclear energy, explains why the situation is so dangerous.
"Any nuclear plant can have an accident, and when you put it in the middle of a war zone, there all kind of things that could go wrong, including the possibility that cooling water may not be available, making the handling of hazardous technology like nuclear technology even harder."
