Each day of the Games we will bring ten facts you may or may not know about the great sporting spectacle that is the Olympcs. Today puts the cyclists and swimers in focus
Today's men's cycling road race, which promises a good chance of GB's first gold for Manxman Mark Cavendish, is the longest event at each Games - and this year's, at 250km (155.3 miles), is the longest yet. A word of warning, though: in 2008 Cavendish was the only member of the men's track cycling team to go home without a medal ...
In Rome in 1960 the Russian cyclist Viktor Kapitonov staged a dramatic sprint to cross the line first ... only to discover there was another whole lap of the nine-mile circuit to go. He managed to collect himself, and led the pack over the finishing line again next time round to win gold.
The tennis gets at Wimbledon. In 1908, Olympic tennis was also played at Wimbledon, although it was not at the current site but at the All England Club's former home in Worple Road (still visible from the train as you approach Wimbledon from the south). After a spate of withdrawals in the ladies' singles, Britain's Dora Boothby won the silver medal despite losing her only match - the Olympic final. (There was also an indoor event in n1908, held at Queen's Club near Earls Court. Tennis did not feature in the 1948 London Olympics).
The beach volleyball starts today at Horse Guards Parade. It's been an Olympic event since 1996, when the women's final was an all-Brazilian affair, won by Sandra Pires and Jackie Silva: the 34-year-old Silva had played indoor volleyball at the Olympics in 1980 and 1984.
The first 2012 medals in fencing, which gets under way today at the ExCeL, will be in the women's foil event. In 1956 this was won by Gillian Sheen, a London dentist, who remains the only British fencer to win Olympic gold.
Michael Phelps' bid to become the most bemedalled Olympian of all time starts tonight, when he defends his 400m individual medley title. Going into the Games, 27-year-old Phelps had 16 Olympic medals - a record 14 of them gold - just two behind the alltime record of the Russian gymnast Larisa Latynina, who won 18 between 1956 and 1964.
The men's 400m individual medley final in 1972 produced one of the closest finishes in Olympic history: Sweden's Gunnar Larsson was eventually adjudged the winner by two-thousandths of a second from the American Tim McKee. The regulations were changed after this, and the race would now be considered a dead heat.
At Melbourne in 1956 the men's 400m freestyle had a popular home winner - the Australian teenager Murray Rose. He was a vegetarian, nicknamed the "Seaweed Streak", and proved it wasn't a fluke by retaining his title at Rome in 1960.
One of Britain's most popular swimmers, Sharron Davies, took silver in the 400m individual medley at Moscow in 1980. Davies, now an eye-catching poolside interviewer, was then 17, and was beaten only by a new world record from Petra Schneider, part of an East German team widely suspect of being fuelled by illegal drugs.
The shooting events, which start today, were moved to the Royal Artillery Barracks in Woolwich after concerns were expressed that the original site - the long-established rifle range at Bisley, near Woking in Surrey - was too far out of London. The first medals of the 2012 Games are likely to be handed out here. In the men's 10-metre air pistol event, Wang Yifu of China won gold, silver, silver and gold at successive Games from 1992 to 2004.