Ever been mesmerized by the swirling colors of Grand Prismatic Spring and wondered what fuels that otherworldly boil? It turns out that beneath the wild expanse of Yellowstone National Park lies one of the most closely watched volcanic systems on Earth.

Scientists found that a "cap" of bubbles and magma stands between the magma reservoir underneath Yellowstone National Park and a volcanic eruption.

Geoscientists have discovered a magma cap at Yellowstone National Park that is likely playing a critical role in preventing a massive eruption in one of the largest active volcanic systems in the world.