Jason And The Argonauts Pearl, 9.30pm Jason London (above) stars in this miniseries inspired by the Greek myth about Jason's perilous quest to find the coveted golden fleece. In order to reclaim his father's kingdom, stolen by his evil uncle King Pelias (Dennis Hopper), Jason must deliver to him the priceless fleece, considered to be the greatest gift from the gods to man. On board their ship, the Argo, Jason and his team of adventurers begin their journey to the island of Colehis. There, according to blind prophet Phineas (Derek Jacobi), an enchanting and beautiful sorceress named Medea (Jolene Blalock) faithfully guards the fleece. Against impossible odds and overwhelming obstacles - including terrifying monsters and an army of beautiful but murderous women ruled by Hypsipyle (Natasha Henstridge) - Jason is determined to complete his task. Equally adamant to see he doesn't is Zeus (Angus MacFadyen), the king of all gods, who is jealous that his wife, Hera (Olivia Williams), has taken a fancy to the young mortal. Also starring Frank Langella. Going To Extremes: Cold World, 12.05am Travel writer and geographer Nick Middleton (above) ventures to Siberia to experience extreme cold. In this remote region of gold mines and ghostly gulags the average temperature from December to February is minus 47 degrees Celsius. Here human breath freezes upon exhalation, and drops to the ground with an audible tinkering, forty per cent of locals have lost fingers through frostbite while changing the wheels of their cars, and milk is not sold in bottles, but in frozen chunks. Horizon: Anatomy Of An Avalanche BBC World, 5.10pm In February 1999, a catastrophic avalanche at Galtur in Austria claimed 31 lives. Over the next six months a team of scientists pieced together the extraordinary chain of events that led to the disaster. By working out the wind and weather conditions at the time of the disaster, and dissecting every layer of snow, the scientists meticulously calculated the complex physics underlying this massive avalanche. The results revealed unexpected new information about how avalanches work. The scientists were able to peer inside the avalanche as it was happening, providing information about the way in which snow accumulates, and the effect that different layers have as they churn around inside the massive flow.