Guy Martin concludes his Chinese adventure with his toughest ever physical challenge. He wants to break the record for the fastest crossing of the Taklamakan Desert on a bicycle. The Taklamakan is known as the desert of death because of summer temperatures that average 40C, sand storm winds that can reach 150mph, and the local legend that once you enter the desert you never come out. Guy must travel 341 miles along the world's longest desert highway in less than 47 hours, a record set in 2014 by two keen British cyclists who only stopped once for a four-hour sleep on a sand dune. They described it as the worst two days of their lives. It's a mental challenge as well as a physical one. In the desert's cold morning air, the metal in Guy's bones aches, a legacy from his motorcycle injuries. Old lorries spurting out thick black fumes constantly thunder past him and pose the biggest threat as the sun sets on the unlit road.