The 132 billion euros feat of engineering and human ambition that is the International Space Station turns 20 today. Why today? Because on November 20, 1998, the first ISS module was launched into space by a Proton rocket.
While the ISS is easily recognisable with its distinctive array of solar panels - and while it's a regular feature on stargazing phone apps - many of us don't really know what the ISS does, exactly.
