The O2 Arena

The arena sits inside the Millennium Dome on the Greenwich Peninsula, a dome-shaped building 365 metres in diameter and 52 metres high, raised for an exhibition marking the turn of the third millennium. The Millennium Experience closed at the end of 2000, and in December 2001 the dome was leased to Meridian Delta Ltd for redevelopment as an entertainment complex, with an indoor arena among the plans.

Construction ran from 2003 to 2007. Cranes could not be used inside the dome, so the arena's roof was assembled on the ground beneath it and then lifted, and the building was raised around the roof; the finished arena building takes up 40 per cent of the dome. It was designed to reduce the echo that troubles older arenas used for concerts, and its seating and floor can be reset between ice rink, basketball court, exhibition hall and concert stage. In December 2004, after the dome's interior had been cleared but before building work began inside it, the shell served as the main venue for the homelessness charity Crisis and its annual Crisis Open Christmas. The arena opened on 24 June 2007, named for its sponsor, the telecommunications company O2.

In 2007 the venue sold over 1.2 million tickets while open only 200 days a year, putting it third among the world's concert and family-show venues, narrowly behind Manchester Arena on 1.25 million and Madison Square Garden on 1.23 million. In 2008 it was the world's busiest music arena.

Michael Jackson was to have opened a fifty-show residency at the arena, This Is It, in July 2009; he died on 25 June, eighteen days before the first scheduled show. During the 2012 Summer Olympics and Paralympics the building was called the North Greenwich Arena, under Olympics regulations on corporate sponsorship of event sites. Country to Country, billed as Europe's largest country music festival, has run there since March 2013, drawing over 20,000 each year, and the arena held the ATP World Tour Finals from 2009 to 2020.

On 18 February 2022 Storm Eunice shredded large sections of the fabric roof, forcing the evacuation of 1,000 people and the closure of the venue; repairs were carried out and it reopened as planned on 25 February for a UB40 concert. On 15 October 2022 Claressa Shields beat Savannah Marshall there, the first time two female boxers had headlined at a major venue in the United Kingdom, on the first all-female boxing card held in the country.

T1 of the League of Legends Champions Korea took their fifth title against Bilibili Gaming of China's League of Legends Pro League in the World Championship final held there on 2 November 2024. Babymetal became the first Japanese act to headline and sell out the arena on 30 May 2025, and All Elite Wrestling's Forbidden Door on 24 August 2025 drew 18,992, a record for professional wrestling at the venue. The building is owned by Homes England; as of 2023 the arena ranked third in the world for music ticket sales, and it has the third-largest seating capacity of any indoor venue in the United Kingdom, behind Co-op Live and Manchester Arena.