Robot Sub Explores Giant Canyon

Using Britain's ISIS robot submarine - a van-sized bundle of high-technology - researchers are for the first time able to view previously hidden features up to 5km (three miles) deep in the Nazare Canyon. The canyon extends out into the eastern Atlantic from the seaside town of Nazare, north of Lisbon - long plotted on maps but until now never properly studied. To the amazement of scientists, the shape of a shark appeared at a depth of 3,600m (12,000ft) - far deeper than sharks are usually found. On the sides of the canyon, beneath the overhanging edges of the giant cliffs, cold-water corals are seen clinging to the rock, part of a highly active ecosystem well below the limits of sunlight...