By creating a new map of Antarctica’s subterranean landscape, researchers have uncovered a vast topography of previously hidden hills, ridges, and even entire mountain ranges lurking miles beneath its frozen exterior. Previous approaches have relied on on-the-ground and aerial missions to use radar to sound out the continent’s subsurface features. But the barren landscape is intimidatingly vast, and these missions can be separated by dozens of miles, leaving scientists with an incomplete picture, which itself can only really guess at what’s trapped below all those miles of ice. According to an editor’s summary of the study, the Antarctic’s subsurface landscape is so mysterious that we know less about it than we do Mercury. It isn’t perfect, according to University of Texas at Austin glaciologist Duncan Young, who wasn’t involved in the study.