You’re not going to get down there to see them, short of some kind of mega-serious seismological catastrophe, but scientists have recently discovered there are vast mountain ranges hidden deep underground. A massive earthquake in Bolivia in 1994 shook the earth so violently, Princeton researchers were able to read the seismic waves generated to map the topography of the mantle to a depth of 410 miles below the surface, in the transition zone between the mantle’s upper and lower levels. They found peaks that may be taller than Everest and entire mountain ranges. “In other words, stronger topography than the Rocky Mountains or the Appalachians is present at the 660-km (410 miles) boundary,” said Princeton’s Wenbo Wu. Photo: Kyle McKernan, Office of Communications.