As of this week, humans have spent 15 continuous years living off the Earth thanks to NASA and the orbiting International Space Station. The first crew moved onto the ISS in November 2000, with a total of 220 people living on board in the intervening years, a group representing 17 countries. The US and Russia have sent the most representatives, followed by Canada and Japan. The station started off as three rooms, blooming to 13 with the current station boasting a mass of almost one million pounds.
According to NASA, more than 1,700 experiments have been carried out on the ISS, with 189 spacewalks. Construction of the station began in 1998, with NASA hoping to keep the structure in operation until 2024. "It [ISS] has taught us about what's possible when tens of thousands of people across 17 countries collaborate to advance shared goals," NASA Administrator Charles Bolden said in a statement.
Here are 50 pictures of the ISS across the years: