In a similar way to the modern pentathlon, athletes competing in the triathlon have to excel at not just one, but three sporting disciplines. Triathlon is made up of swimming, cycling and running and came part of the Olympic sport line-up in 2000, at Sydney, Australia. First there's a 1500m swim in open water to complete, followed by a 40km cycle and then a 10km run - and that includes switching from a wet suit to cycling shoes en route.

In order to accommodate the needs of the triathlon at the 2012 Olympics in London, Hyde Park, the largest Royal Park in London, will be hosting the event. It's already home to the famous Serpentine Swimming Club and is a great setting for this outdoor sport. A temporary grandstand will be built, with more space for spectators to watch the action around the course.