Chernobyl's Elephant's Foot still sits inside the damaged reactor as a highly radioactive corium mass. Its weakening but persistent radiation keeps it central to safety research and disaster memory.

Some historical events are so catastrophic they resist comprehension. And yet they compel us to try to understand them, again and again. Chernobyl is one of them. On April 26, 1986, at 1:23am, Reactor ...