Each day of the Games we will bring ten facts you may or may not know about the great sporting spectacle that is the Olympics. Today some famous and infamous events from the water are in focus
In the pool, the men's 100m breaststroke has produced British success in the past: Adrian Moorhouse won in 1998, and Duncan Goodhew in 1980, while David Wilkie (who won the 200m) narrowly missed out on double gold in 1976. Competitors these days have a cushy number compared to their predecessors: in Paris in 1900 there was a 200m obstacle race, in which the swimmers had to navigate over a pole then under and over rows of moored boats. And four years previously in Athens the home nation assured itself of a clean sweep of the medals by staging a 100m race for sailors, restricted to members of the Greek Navy.
Today's women's swimming highlights include the final of the 400m freestyle, memorably won in Beijing by Rebecca Adlington. She's still ranked No. 1 in the world, although a couple of feisty Aussies will be hoping to knock her off the top of the podium here. This event first featured in the Olympics in Antwerp in 1920: the winner, the American Ethelda Bleibtrey, had been arrested the previous year for "nude swimming", after shockingly removing her stockings before going for a dip in Manhattan.
One of the highlights of Sydney 2000 was the Australian quartet's upset victory over habitual champions the United States (they'd won all seven previous stagings of the race) in the men's 4x100m freestyle relay: 17-year-old Ian Thorpe powered them home. South Africa got in on the act in 2004, before Michael Phelps helped restore the American Way in Beijing.
The women's cycling road race - like the men's race, it loops into Surrey then finishes on The Mall - is the event that brought Britain their first gold medal in 2008, when Nicole Cooke memorably sprinted up a Beijing hill in the rain. Cooke is back again, although Emma Pooley and Lizzie Armitstead are also medal hopefuls for Team GB.
The boxing gets under way today at the ExCeL, with the early rounds of the men's light- and welterweight competitions. The lightweight champion in 1956 was Scotsman Dick McTaggart, one of 18 children and the only Briton ever to win the Val Barker Trophy, the special award for the most stylish boxer at each Olympics. Amir Khan took silver at the same weight in Athens in 2004.
Stuart Pearce's Great Britain football team have another run-out today, against the United Arab Emirates at Wembley. The draw against Senegal a couple of days ago was GB's first match in the Olympics since 1960. Britain do, however, share the record for the most gold medals (three) with Hungary, although their last win was 100 years ago, in 1912 ...
Greenwich sees the start of the women's gymnastics, with - for the first time in living memory - Britain having a decent chance of topping the podium, thanks to Beth Tweddle, who has a clutch of world titles to her name. Actually Britain's only medal in women's gymnastics so far was a bronze in the team event in 1928 - the first year the ladies were (rather reluctantly) allowed to take part.
The water polo tournament gets under way today at Olympic Park. The sport has a chequered history at the Games: in 1956 a match between the Soviet Union and Hungary, three weeks after Russian tanks had rumbled into Budapest, degenerated into a brawl and was eventually abandoned. And in St Louis in 1904 the event was conducted in water so filthy that several competitors fell ill (this one is no longer included in the official records as the only participants were American club teams).
The sailing, one of Team GB's strongest suits in recent Games, starts today in Weymouth and Portland in Dorset. The first races are in the Finn class - in which Ben Ainslie is the favourite for a fourth successive gold - and the Star, where Iain Percy and Andrew Simpson are aiming to reprise their success in Beijing. Sailing is the most regal of Olympic events: King Olav V of Norway won gold in a six-metre yacht in Amsterdam in 1928, while King Constantine of Greece did likewise in a Dragon class boat in 1960.
At Greenwich Park it's the second day of the dressage portion of the three-day event, which confusingly lasts four days. Britain has won the team competition three times - in 1956, 1968 and 1972 - and the individual gold twice (Richard Meade in 1972 and Leslie Law in 2004). Princess Anne took part in 1976 - she was famously the only female competitor that year not to be subjected to a sex test - while her daughter Zara Phillips is in the British team this time. Her father, Mark Phillips, a team gold medallist in 1972, is coaching the American team in London. Double world champion Mary King is appearing in her sixth Olympics.