The O2 Arena is a large indoor arena located in London, England. Opened in 2007, it has a seating capacity of up to 20,000 people, making it one of the largest venues in the country. The arena hosts a variety of events, including concerts, sports competitions, and exhibitions. Designed by architect Richard Rogers, the O2 Arena is part of the larger O2 entertainment complex, which includes restaurants, bars, and a cinema. Its distinctive dome shape is a recognizable feature of the Greenwich skyline, and it has become a popular destination for both locals and tourists.