The O2 Arena, commonly known as The O2, is a multi-purpose indoor arena in the centre of The O2 entertainment district on the Greenwich Peninsula in southeast London. It opened in its present form in 2007. It has the third-highest seating capacity of any indoor venue in the United Kingdom, behind Co-op Live and Manchester Arena, and in 2008 wa…The O2 Arena, commonly known as The O2, is a multi-purpose indoor arena in the centre of The O2 entertainment district on the Greenwich Peninsula in southeast London. It opened in its present form in 2007. It has the third-highest seating capacity of any indoor venue in the United Kingdom, behind Co-op Live and Manchester Arena, and in 2008 was the world's busiest music arena. As of 2022, it is the ninth-largest building in the world by volume with a diameter of 365 metres and a height of 52 metres.