The European Space Agency took a handful of its finest astronauts and threw them inside a space shuttle and had them simulate a 520-day mission to Mars. While locked away the crew had to perform experiments, communicate with their Earth base, and do other space mission-related things. Fortunately for us they also equipped the shuttle with a gang of cameras and allowed the astronauts to record the going-ons. Watching all 520 days would be an extremely daunting and boring task, so the ESA compressed the entire mission (dubbed the "Mars 500") into a breezy and compact 15-minute. Enjoy.