It’s very difficult to know what lies beneath a blanket of kilometres-thick ice, so it is hardly surprising that scientists have long contested the shape and geology of the ancient supercontinent from which East Antarctica formed over a billion years ago. An ESA-funded study can now lay some of this conjecture to rest. Using sensors on aircraft to measure changes in the gravity and magnetic signatures of the different rocks under the ice, scientists have discovered a huge bay the size of the UK formed part of the edge of East Antarctica.