Mexico City was a controversial choice because of the city's high altitude which meant that the air contained 30% less oxygen than at sea level.

The conditions proved disastrous for endurance athletes but there were world records in all of the men's races that were 400m or shorter, including both relays, and in the long jump and triple jump as well.

Bob Beamon's first attempt in the long jump was so long that the optical measuring device slid off its rail before it reached Beamon's point of impact and the judges had to use a metal tape measure to record the spectacular distance of 8.90m - a world record which would last for 22 years.

Mexico was also the birthplace of the Fosbury flop - the high jump style perfected by American Dick Fosbury which won him the gold medal.

Britain's David Hemery won gold in the 400m hurdles.

Sex testing for women was also introduced for the first time while the Games also saw the first drug disqualification, as Sweden's modern pentathlete Hans-Gunnar Liljenwall tested positive - for excessive alcohol.

The athletics, cycling, rowing, canoe, swimming and equestrian competitions were timed manually and electronically but for the first occasion the electronic time was the official one.

British gold medals: 6