One of Auckland's nicknames, the "City of Sails", is derived from the popularity of sailing in the region. 135,000 yachts and launches are registered in Auckland, and around 60,500 of the country's 149,900 registered yachtsmen are from Auckland, with about one in three Auckland households owning a boat. The Viaduct Basin, on the western edge of the CBD, hosted three America's Cup challenges (2000 Cup, 2003 Cup and 2021 Cup).