The station was unmanned until nearly two years later, when American astronaut William M (Bill) Shepherd along with Russian cosmonauts Sergei Krikalev and Yuri Gidzenko arrived on board on October 30 2000.
However, it was not complete until 2011, when the final module was installed (it looks set to be decommissioned by 2028). The ISS has been inhabited every day since, and crew members carry out research they would not be able to do on Earth.
In its 20-year history, 230 individuals have been on board the station, originating from 18 different countries
Sixteen nations were involved in its construction. In addition to the US and Russia, those were: Belgium, Brazil, Canada, Denmark, France, Germany, Italy, Japan, the Netherlands, Norway, Spain, Sweden, Switzerland and the UK.