On November 20, 1998, a relatively small man-made satellite was launched from Kazakhstan to begin an orbit that's still taking place today. Over the 15 years that followed, that first module was added on to and expanded like the most expensive set of tinker toys mankind has ever created to become the International Space Station.
While it was only fully completed in 2011, Wednesday marks 15 years since that first launch and the start of probably the largest cooperative construction project involving multiple nations in human history. During that decade and a half, over 1,500 science experiments have taken place at the ISS, which is also considered one of the United States' National Laboratories.
Representatives from 68 nations have been involved in ISS research, and 15 different nationalities have actually visited the station. Crews on the ISS have eaten about 25,000 meals since 2000 and done over 1,000 hours of spacewalking.
We've compiled 15 of the most historic and memorable moments from 15 years of the ISS, please check them out in the gallery below, and let us know in the comments if you have any other ISS memories we've missed.