In 1849, several hundred thousand Americans and Europeans began streaming across "The Great American Desert" bound for the gold fields of California. Their dream was to strike it rich, but if the Gold Rush epitomizes the American Dream, their trek through the wilderness became the worst of nightmares. 150 years later, British cycling journalist John Stuart Clark retraces the same roads, rivers and trails taken by the Forty Niners, struggling across 3,000 miles of inhospitable terrain, battling violent sandstorms and withering heat.