The O2 Arena, referred to as North Greenwich Arena during the 2012 Summer Olympics and 2012 Summer Paralympics, is a multi-purpose indoor arena located in the centre of a major entertainment complex on the Greenwich Peninsula in south-east London. Its started off life in 2000 as the Millennium Dome, and is the world's largest building by measure of floor space. The Emirates Air Line cable car spans the River Thames between North Greenwich and the Royal Docks.