On the afternoon of September 10, 1969, Chester McQueary laid his belly onto the dirt of rural Rulison, Colorado. A few seconds later, a nuclear bomb two and a half times the size of the one that dropped on Hiroshima exploded less than two miles below him.

As a 33-year-old anti-nuke hippie, McQueary was protesting the blast, an experimental operation attempting to retrieve natural gas from deep below the earth. A five-mile quarantine zone had been set up around the site with the understanding that the blast would not go off if humans remained within the boundary. But the project had experienced repeated delays already, and despite McQueary and his crew setting off smoke flares to announce their presence, the 40-kiloton nuclear device was, in fact, detonated.