Scientists have used echo-sounding methods to study the ocean floors in the Arctic and Antarctic.
See also: Remains of mystery sea creature found on Welsh beach
See also: 'Walking shark' discovered on ocean floor
Their research shows how the ocean floors were scraped by ice sheets and glaciers.
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Dried-out treetops protrude from crystal water in an eerily beautiful liquid landscape - the result of an enormous earthquake more than 100 years ago. As Lake Candy sits 2,000m above sea level, the temperatures here remain icy: they rarely exceed 6C. This coldness has preserved the submerged trees. Great pine cones still remain on the trees underwater from 100 years ago: you can see into the great depths of the lake through the clear mountain water.