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.
Dr Kate Winter from Northumbria University, UK, and colleagues found the hidden features with radar.
Her team says the canyons play a key role in controlling the flow of ice.
And if Antarctica thins in a warming climate, as scientists suspect it will, then these channels could accelerate mass towards the ocean, further raising sea-levels.
“These troughs channelise ice from the centre of the continent, taking it towards the coast,” explained Dr Winter.
“Therefore, if climate conditions change in Antarctica, we might expect the ice in these troughs to flow a lot faster towards the sea. That makes them really important, and we simply didn’t know they existed before now”