Sometimes, you forget about things that happened during your own lifetime. For instance, I’d completely forgotten that, back in 1997, cosmonauts accidentally ran an unmanned spacecraft full of garbage into the side of the space station Mir, temporarily knocking out power and sending the space station into an uncontrolled spin. NASA has the full story, an oral history from an astronaut who was on board Mir at the time, and some nifty animations showing what happened.