Scientists have discovered three vast canyons in one of the last places to be explored on Earth - under the ice at the South Pole. The deep troughs run for hundreds of kilometres, cutting through tall mountains - none of which are visible at the snowy surface of the continent.

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Scientists have discovered three vast canyons in one of the last places to be explored on Earth - under the ice at the South Pole. The deep troughs run for hundreds of kilometres, cutting through tall mountains - none of which are visible at the snowy surface of the continent.