A massive ancient subglacial trough -- deeper than the Grand Canyon -- exists under the ice of Antarctica, a team of British experts says. Scientists from a number of British universities and the British Antarctic Survey discovered the massive valley during three seasons of charting the Ellsworth Subglacial Highlands -- an ancient mountain range buried beneath several kilometers of antarctic ice -- using data from satellites and ice-penetrating radars towed behind snowmobiles and on-board small aircraft. The massive subglacial valley is almost 2 miles deep, almost 190 miles long and up to 15 miles wide. In places, the floor of this valley is more than 6,500 feet below sea level, the researchers said. "The discovery of this huge trough, and the characterization of the surrounding mountainous landscape, was incredibly serendipitous," Newcastle University physical geographer Neil Ross said. "We had acquired ice penetrating radar data from both ends of this huge hidden valley, but we had no information to tell us what was in between," he said. "Satellite data was used to fill the gap, because despite being covered beneath several kilometers of ice, the valley is so vast that it can be seen from space." A moving ice field carved the deep valley and its surrounding mountains millions of years ago, the scientists said. "To me, this just goes to demonstrate how little we still know about the surface of our own planet," Ross said. "The discovery and exploration of hidden, previously unknown landscapes is still possible and incredibly exciting, even now."