Out of the water: The story goes that European gymnasts once had nothing better to do than practice their moves on the beach. So they put two and two together and starting jumping into the water. That doesn't make total sense, but by the end of the 19th century diving was a competitive sport.

Splashing out: First staged in St Louis in 1904, the platform dive attracted just five competitors - all either German or American. In a dispute over the rules, the Americans felt that the manner in which the diver hit the water was important, while the Germans, who attempted more difficult dives but produced the odd belly-flop, contended that landings didn't matter.

Spring in their step: The springboard event joined the platform in 1908 in London and the Americans ruled for decades after. In 1924 in Paris, Albert White became the first diver to win both the springboard and platform while Sammy Lee won two platform titles back to back in 1948 and 1952.

Plain's descent: Plain high diving survived a couple of Games before ending up in the discontinued heap in 1924. The plain high dive was just that - nothing fancy, no twists and no somersaults.

Wearing of the green: Eddie Heron won his first of 25 Leinster high diving titles at 13 and in 1933 became the only Irishman to win the British Open title. In the platform event, he made the Irish team for the London Olympics in 1948 and, by his retirement two years later, had won 18 Irish platform titles and 16 springboard titles.

From a distance: The platform (also known as the high board or high dive) is 32 feet, nine inches (10 metres) above the water, and the springboard is set at a height of nine feet, 10 inches (three metres).

Total degrees of difficulty: Competitors can choose to perform dives that have been rated according to their degree of difficulty, or they can create their own. Points are awarded for approach, take-off, elevation, execution of movement and entry into the water. The scores of the seven judges are multiplied by a coefficient that is determined by the difficulty of the dive.

Pike or tuck: The most basic diving positions include the pike (body bent at the waist with legs straight) or the tuck (knees and hips bent, with the knees held together against the chest).

The Louganis factor: Of Samoan and northern European ancestry, Greg Louganis was given up for adoption by his 15-year-old parents. Heavily taunted at his Californian school for being dyslexic, Louganis was smoking both tobacco and marijuana aged 12 and depended heavily on alcohol in his teenage years. But diving soon became his refuge and at 16 he made the Montreal Olympics, finishing second in the platform and sixth in the springboard.

The heights: Louganis was a certainty for both titles in Moscow but missed out because of America's boycott of the games. In Los Angeles in 1984, he won the springboard by an unprecedented 94 points, and in the platform became the first man ever to score over 700 points. Blood on the pool floor: Four years later in Seoul, Louganis was leading the preliminary round of the springboard when he stepped up for his ninth dive, a reverse two-and-a-half somersault in the pike position. But in failing to push out far enough, he hit his head on the board and fell clumsily into the water.

Sink or swim: Despite being cut, 35 minutes later he was back on the board and qualified for the final, where he became the first man to win both the springboard and platform twice in row. But seven years after Seoul, Louganis came out with his full story. Six months before the Olympics, he had tested HIV-positive and was taking the drug AZT every four hours. Only later did he learn that the blood from his head would have been diluted enough in the water to render it from being dangerous, but he did risk contamination to his coach and doctor who had treated his wounds. Both later took AIDS tests that proved negative.

The Sydney surprise: New to the Olympic programme this year will be synchronised diving, where a pair of competitors must perform a combination of dives in both springboard and platform. Expect to be truly blurry-eyed.