It's no secret that the American military is a fairly messed-up institution. If it's not being exposed for failing to combat the high rates of sexual assault and rape of female officers in the Oscar-nominated documentary The Invisible War, it's being investigated for concealing the deaths of multiple civilians in Afghanistan during the occupation of the country (read Jeremy Scahill's book Dirty Wars if you're interested in that one).

Despite that sullied reputation, it may come as a shock to many to learn that, in 1966, the American military accidentally dropped four atomic bombs on Spain but managed to minimize the incident to the extent that it's been virtually washed clean from history. A mixture of savvy PR from the US government and patchy reporting from international media means that most of us don't even know it happened.

So here's what happened: on January 17, 1966, a US B52 bomber collided with a refueling aircraft in Spanish airspace. The crash meant that four hydrogen bombs were dropped. Two hit the ground at speed, imploding and releasing plutonium into the soil of the Andalusian town of Palomares. Meanwhile, parachutes were deployed on the other two bombs. One hit the ground without detonating and the other landed in the Mediterranean Sea still intact. It wasn't until late last year that America agreed to clean up the resulting contamination and ship the soil back to the US, where it will probably end up in Nevada.

Professor John Howard is an American academic, author, and photographer. He has spent the last five or so years traveling to Palomares in order to document the remains of the nuclear disaster with his camera. While he can't photograph the remains of the plutonium—despite the fact it still sits within the soil—he instead captures the ramifications of this incident on the people, economy, and landscape of Palomares.