Speed World, 1.10am Some people go to extraordinary lengths in pursuit of high speeds. Whether in a supersonic car or travelling at 450km/h in a boat, they reach speeds most people never experience. In each episode of this six-part series, British presenter Jeremy Clarkson (above) investigates a different aspect of speed and talks to people on the cutting edge of hyper travel. Clarkson crosses the world, meeting desert racers, speed skiers, test pilots, skydivers and astronauts, including heroes such as Chuck Yeager, Richard Noble and Michael Schumacher. In the first episode, Clarkson asks why people react differently to high speeds. He talks to experts and thrill-seekers and puts their theories to the test. Clarkson's first experiment is to force his mother on to the world's fastest roller-coaster in Blackpool, England, to compare his reaction with hers - he is elated but his mother is terrified. Next, Clarkson travels to Innsbruck, Austria, to meet the British Army's four-man bobsleigh team. He hears horrific accounts of fatal accidents and reluctantly gives it a go. Finally, he meets the fearless drag-boat racers of Chowchilla, California. They accelerate from 0-320km/h in just five seconds.