Yellowstone National Park has long captured the imagination of scientists and the public alike, particularly due to its supervolcano, which has featured prominently in disaster films and existential musings.

A park scientist noticed it about two weeks after a hydrothermal explosion along a boardwalk during the park’s overactive summer.

Today, Yellowstone remains a place of low volcanic risk. Sure, there are sometimes small explosions stoked by hot water and steam. But it's mostly thermal pools and awesome geysers, reminding us of what could potentially awake, one distant day.