In 1962, the US government exploded a nuclear bomb over Honolulu. This had a number of unexpected effects, including the seven-minute-long display of an artificial aurora borealis you see above.
After the Van Allen belt was discovered in the early 1960s — the belt of free particles held in place above the Earth by the Earth's magnetic field — scientists mulled over the existence of this new phenomenon and thought, "Eh. Let's shoot a nuke at it." The nuclear test was called Starfish Prime, and it was set off about 250 miles above the Pacific ocean. The explosions were clearly visible from Honolulu; amazingly, the residents were by-and-large okay with this, even going so far as to organize viewing parties.
One unexpected result of the bomb was the taking out of a communications satellite launched shortly afterwards. More spectacularly, at least for those viewing the blast, was a seven-minute-long light show. Particles released from the bomb struck atmospheric molecules, heating them up and lighting the sky. It must have been pretty to see, but I'm glad I wasn't there for it.