TV Guide Dave ja vu Sunday

On the fourth leg of his journey through the continent, Simon travels through three of the world's most extreme environments as he takes in the salt flats of Bolivia, Brazil's Pantanal wetland region and Paraguay's Chaco Forest. In Bolivia, he meets a family making a living carving salt from the vast white expanse of the Uyuni flats, while in Brazil he has a close encounter with South America's apex predator, the jaguar. In Paraguay, Simon visits a Mennonites school, where traditionally clothed children are drilled in Bible texts and there are no smartphones to be seen

The last leg of Simon's journey through South America takes him from Chile's Atacama Desert right down to Tierra Del Fuego, the most southerly inhabited place on Earth. In the Atacama, one of the driest places on the planet with is as little as 1mm of rain per year, Simon discovers shocking evidence of human pollution

Paul Whitehouse and Bob Mortimer return to Scotland for their latest fishing trip. Having failed to catch a salmon in the River Tay, they hope to have more luck on the Tweed. They begin their journey at the isolated Bemersyde Estate before moving on to the Bridge Pool at Kelso, one of the most famous salmon fishing spots in Scotland. They also try their hand at boat fishing and receive some mystical predictions from a familiar face

Sandi Toksvig asks questions on the theme of 'radio activity', with Joe Lycett, Shazia Mirza, Josh Widdicombe and Alan Davies trying to come up with interesting answers - while avoiding the most obvious ones

Paul Whitehouse and Bob Mortimer are joined by singer and conservationist Feargal Sharkey for a trip to the River Lea in Hertfordshire, where Paul used to fish for perch with his friends when he was a teenager. Bob reads up on the wise words of 17th-century angler Izaak Walton and prepares a riverside picnic that brings back fond memories and leads to a reflection on the differences between teenage life in their 1970s youth and the present. Setting up home in a narrowbooat, he also prepares a dish Paul's mother used to make - corned beef and potato pie