The ATP World Tour Finals (also known as the Barclays ATP World Tour Finals for sponsorship reasons) is a professional men's tennis tournament played on indoor hard courts and is held annually in November at the O2 Arena in London, United Kingdom. The ATP World Tour Finals are the season-ending championships of the Association of Tennis Professionals (ATP) World Tour, featuring the top eight singles players and doubles teams of the ATP Rankings. The tournament was first held in 1970. The current champions (2015) are Novak Djokovic in singles and Jean-Julien Rojer and Horia Tecau in doubles.