Madagascar: Celebs take on treacherous tracks. Angus Deayton and Mariella Frostrup battle across broken bridges as they drive up Madagascar's eastern coast on roads mired in mud. [S]
Georgia: Twenty Twelve co-stars Hugh Bonneville and Jessica Hynes face an Olympic-sized task as they take a terrifying road trip through the deadly, winding mountains of Georgia. [S]
Bolivia: Funny men Phill Jupitus and Marcus Brigstocke find that their high-altitude road trip in South America is no joke as they grapple with Bolivian bandits and the Road of Death! [S]
Nepal: Comedians Rhod Gilbert and Greg Davies won't be laughing too much as they dodge reckless drivers, floods and landslides on an ambitious drive through mountainous Nepal. [S]
Alaska: And you thought the M25 was bad. Sue Perkins and Charley Boorman trek across Alaska on the notorious Dalton Highway, battling Arctic conditions on a glorified dirt track. [S]