Documentary Watch

Naked Planet Pearl, 8.30pm This new series, commissioned by Britain's Channel 4, explores some of nature's most extraordinary wonders, from the Niagara Falls to Ayers Rock. It begins in the heart of the Holy Land, with the Dead Sea (above) and its pillars of salt - standing in the deepest slit on any continent, 430 metres beneath the ocean. The Dead Sea water is so salty just one cup of it can kill, yet bathers flock there. This documentary enlightens us to how this extraordinary sea was created, and about the legends of its lost civilisations. King David was among those believed to have taken sanctuary in its caves, where the Dead Sea scrolls were also found.

Eco-Challenge: Australia World, 9pm Forty-eight teams from 15 countries race across 187 kilometres of the Australian outback, with Discovery channel's cameras never far behind. They run, cycle, horse ride, climb and raft their way through the unforgiving terrain. Along the way they encounter venomous snakes, crocodiles, dehydration and the disappointment of failure. Despite all that, they think this is the most exhilarating experience of their lives.

Savage Planet World, 10pm Television's fascination with hostile places continues with this new series, which begins by featuring the deadly crater lakes found in the Philippines, Cameroon and America's Seattle, for instance. Dazed survivors of 'exploding' volcanic lakes tell of their encounters.