Comedian Sue Perkins and adventurer Charley Boorman travel across Alaska to the notorious Dalton Highway, a dirt track built to support an oil pipeline.

Rhod Gilbert and Greg Davies drive through Nepal where they face floods, landslides, swerving overloaded buses and crumbling mountain roads.

Ben Fogle and Hugh Dennis take a terrifying ride complete with 2,000 foot drops and hairpin bends from the Peruvian Andes to the Amazon jungle.

Friends and fellow comedians Ed Byrne and Andy Parsons brave freezing temperatures, roads of ice and deserted gulags along Siberia's Road of Bones.

Sue Perkins and Liza Tarbuck drive the legendary Ho Chi Minh Trail, a network of dangerous roads hacked through mountains and jungles of Laos and Vietnam.

Comedians Hugh Dennis and David Baddiel face doped-up truckers and a shortage of fuel along religious Ethiopia's death-defying, bone-shaking roads.