One-third of the earth's surface is classified as desert. The writer William Atkins has travelled to eight of the world's hottest, driest places. He tells Andrew Marr about these forbidding, inhuman landscapes.

The Arabian Desert lies mostly in Saudi Arabia but crosses borders from Egypt to Qatar, UAE to Oman. The economic analyst Jane Kinninmont looks at how this shared landscape affects regional politics and culture.

In the 1950s deserts were the preferred places for Britain and America to test their nuclear bombs in secret. The science journalist Fred Pearce explores the human ingenuity - and human error - that has fuelled the atomic age.

Producer: Katy Hickman.