In the West Thumb Geyser Basin in Yellowstone National Park, there's a mudpot between the Grand Loop Road and the parking lot. Among the thousands of thermal features in the park, it doesn't stand out.

That's "Infrastructure Spring." At least, that's what Susan Jennys and her fellow "geyser geeks" call the unassuming but fascinating mudpot.

"Most people drive right on by, and they don't even realize there's a feature there," Jennys said. "It's hiding in plain sight, but it's one of the most fascinating features in Yellowstone."

Every thermal feature in Yellowstone has a natural system of subterranean "plumbing" that feeds water and steam to the surface. "Infrastructure Spring" is unique in that it has claimed human plumbing into its own system.

"The below-ground infrastructure coul

See Full Page