The Yellowstone National Park in the US sits on top of a super-volcano which has laid dormant for 640,000 years. When the last eruption occurred 640,000 years ago, it was reportedly a thousand times the size of the Mount St. Helens eruption in 1980. There have been signs in recent years that the volcano could be becoming active again. Just recently, photos were released by officials at the park, showing that geothermal heat from under the ground is actually melting the asphalt that runs through the park.

Park spokesman Dan Hottle told reporters this week that a 3-mile section of Firehole Lake Drive is now closed because the road has become a "hot soupy mess."

"This road has had this particular issue in the past, but it doesn't happen too often. But it's hard to tell if a thermal area is hotter than normal because it's always fluctuating here. Road closures are business as usual for us," Hottle said.

Hottle also assured reporters that the super-volcano was not "ready to blow," but how can he really know for sure?

In addition to the geothermal activity, the site has also show increased seismic activity in recent years.

A 4.8 earthquake hit the northern part of Yellowstone National Park in March of 2014, after a smaller series of shocks occurred throughout the region.