Sep. 10 was the 50th anniversary of Project Rulison, which was an underground nuclear test conducted in Rulison, Colorado. Its purpose was to determine if a nuclear bomb, detonated underground, could be used to release natural gas.
The answer was, not really, because the bomb will radiate the gas, making it unusable.
But what gave the test extra weirdness was that a handful of protesters tried to stop it by placing themselves on top of it.
As an article on CBS Denver notes:
They believed the scientists wouldn’t actually detonate the bomb if people were inside the closure area above, they were wrong.
The protesters survived, but I'm assuming they must be the only people to have ever been directly on top of a nuclear explosion who lived to tell about it.
An article on vice.com
offers a few details about what it felt like to be in the blast zone:
"There was this great rumble, and we were lifted about six or seven inches off the ground," he recalls. "There were a whole bunch of tremors reverberating through the ground. People down below described seeing ripples flow through the earth, like a rock that had been tossed in a pond."