As challengers Team New Zealand and holders Oracle Team USA contest the 34th America's Cup in radical high-speed 72ft catamarans on San Francisco Bay, BBC Sport takes a look at how the boats have evolved over the 162-year history of the oldest trophy in sport.
1851: US yacht America wins the first trophy, later renamed the America's Cup, in a race around the Isle of Wight of England's south coast.
1887: By the eighth edition of the America's Cup, the boats have changed significantly. American sloop Volunteer (left) beats Britain's Thistle (right) in New York.
1934: Sir Thomas Sopwith's Endeavour, seen here in 2001, is a 40m J-Class yacht with a steel hull and mast and a more modern mainsail and jib configuration. She loses narrowly to US yacht Rainbow in New York.
1983: Fast forward through 132 years of American domination and Alan Bond's 12-metre Australia II, with its controversial winged keel, beats Liberty in Newport, Rhode Island, to take the America's Cup Down Under for the first time.
1983: Australia II's radical new winged keel is kept under wraps through the competition, fuelling the intrigue, aura and infamous bickering of the America's Cup.
1987: Australian 12-metre Kookaburra III wins the defender's trials after last-minute keel modifications but loses out to Dennis Conner's Stars and Stripes in the America's Cup in Fremantle.
1995: Young America unveil the lead bulb on their keel ahead of the US's America's Cup defence against Sir Peter Blake's Team New Zealand.
1995: But the Kiwis onboard the carbon fibre NZL 32, named 'Black Magic', are too strong and win 5-0 to take the Cup to New Zealand for the first time.
2007: Team New Zealand defend at home in 2003 but lose to Swiss team Alinghi back in Auckland in 2003. Four years later Alinghi (right) beat the Kiwis again in Valencia, Spain.
2010: US team Oracle, bankrolled by software billionaire Larry Ellison, challenge holders Alinghi, and after extensive courtroom wrangling take to the waters off Valencia with a giant trimaran.
2010: Oracle's USA 17 is a 90ft, three-hulled giant with a solid wing sail. Alinghi answer with a 90ft catamaran with a bowsprit that takes it to 120ft overall but it is no match for the American monster which wins 2-0.
2013: As holders, Oracle Team USA have the right to determine the boats and format for the next America's Cup and devise a new class of boat, a 72ft catamaran (called the AC72) with a solid 'wing' sail, capable of speeds up to 45 knots (50mph).
2013: Developments to the original AC72 designs have seen hydrofoils added to allow the hulls to rise out of the water to reduce friction and further increase speed.
2013: Last October, Oracle capsize their new AC72 in San Francisco Bay and though no-one is hurt it fuels concerns that the boats are too powerful and difficult to control in certain situations.
May 2013: British Olympian Andrew Simpson is killed when he is trapped under the upturned hill of his Artemis yacht when it capsizes and breaks up in a training accident in San Francisco on 9 May.
August 2013: The competition is in jeopardy after Simpson's death, but a raft of safety measures are implemented and Team New Zealand win the Louis Vuitton Cup challenger series 7-1 against Italy's Luna Rossa to earn the right to face Oracle Team USA in the America's Cup.
September 2013: Oracle are penalised two points for illegally modifying their boat in the warm-up series and so begin the America's Cup already on the back foot. Team New Zealand surge to a 4-1 lead, forcing Oracle to call up Britain's four-time Olympic champion Sir Ben Ainslie from the warm-up crew to tactician. The shore crew also make significant boat changes. The Kiwis reach match point at 8-1 but Oracle surge back to triumph 9-8 in one of sport's most remarkable comebacks.