Colorado’s Unaweep Canyon presents an intriguing geologic mystery – two creeks that flow simultaneously out of the canyon in opposite directions.

The Ute translation of Unaweep Canyon is “Canyon with Two Mouths” or “the Parting of the Waters.” According to Visit Grand Junction, Unaweep “the only canyon in the world to have two rivers flowing out in opposite directions.”

According to Atlas Obscura, an almost imperceptible divide in the middle of the canyon splits the water flow out of the canyon into East and West Creeks, which flow out in their respective directions. The East Creek flows into the Gunnison River and the West Creek streams into the Dolores River.

What makes this geologic phenomenon even more mysterious and intriguing is that it is unclear how it was formed. Atlas Obscura explains how it was once thought to be cut by an ancestral Gunnison River or formed by glaciers in the last ice age. However, Unaweep Canyon is too low for glacial action in the last ice age, and recent core samples indicate that it may have been cut by glaciers as long as 300 million years ago. Uplift of the Uncompahgre Plateau and erosion from the Gunnison River may have exposed the ancient canyon.

In addition to the mysterious geologic phenomenon, Unaweep Canyon offers hiking, mountain biking, and what Visit Grand Junction calls some of the best granite climbing outside of Yosemite National Park.

Visitors can also see the famous ruins of Driggs Mansion, located behind Thimble Rock. According to Atlas Obscura, the mansion was constructed in 1918 by Nunzio Grasso for mining tycoon Laurence Driggs. Today, the mansion’s ruins provide a “haunting backdrop” to the already peculiar canyon.