Scientists have discovered three massive canyons in one of the last places to be explored on Earth – under the ice at the South Pole.
The deep canyons run for hundreds of kilometres, cutting through tall mountains. However, none are visible at the snowy surface of the continent as they are buried under hundreds of metres of ice.
Dr Kate Winter from Northumbria University, UK, and colleagues found the hidden features with radar.
The biggest of the canyons is called Foundation Trough. It is over 350km long and 35km wide.
The two other canyons are also big. The Patuxent Trough is more than 300km long and over 15km wide, while the Offset Rift Basin is 150km long and 30km wide.