Guy Martin has put his body through a lot – but this challenge, which he undertakes in the series's conclusion, is the most gruelling he's done so far.
He's aiming to cycle 341 miles across the Taklamakan Desert – where summer temperatures reach 40°C and sandstorm winds hit 150mph – in under 47 hours, the previous record. Will he be beaten by the Taklamakan, alarmingly known as the 'desert of death'?