The Nature of Things Season 41

South America is a land of extremes. It boasts the world's longest mountain chain, the Andes; the mightiest river, the Amazon; the largest rainforest, the driest desert and the richest sea.

Amanda is an insightful 19-year-old from Timmins, Ontario. She has a three-year-old son and a dilemma: whether or not to be tested for the faulty gene that will bring on Alzheimer's Disease by her mid-30s, as happened with her mother and other generations in her family. It is a disease that always leads to early death.

PENGUIN SHORES is part five of the magnificent six-part BBC series Lost Worlds, covering the amazingly diverse topography of South America, and its remarkable denizens. The world's longest mountain chain stretches from the tropics to the massive Patagonian Ice Sheet of sub-Antarctica. Its icy power dominates the lives of the hardy animals that dare to call it home, making living there one of nature's greatest challenges.

Lost Worlds - A six-part series on the breath-taking natural world of South America takes viewers on a cross-continent grand tour - from the mighty Amazon to the spectacular Andean peaks and the world's driest desert - stopping to view the strange and wonderful array of animals, birds and other wildlife along the way. Produced by the BBC. Narrated by David Suzuki.

Salmon are considered an excellent source of nutrition. And farmed salmon provide it inexpensively. But at what cost? The Price of Salmon explores the complex issues involved with aquaculture.

Albertans have traditionally been proud of their mighty petroleum industry. But lately, they have begun to question how that industry works. Nowhere is this shift more apparent than along the Clearwater River in Central Alberta, near Rocky Mountain House. There, residents are opposing Shell Canada's plans to drill a sour gas well in their area. The sour gas from the well could generate $10,000 a day in gross revenue, to meet today's high energy demands.