It's a spectacular beauty spot, but it's now the site of a horrific family tragedy.
A 911 caller reported: "There was an avalanche. A whole chunk of the mountain just slid down."
The couple's youngest daughter, Gracie, was the lone survivor and was saved when her dad shoved her out of the way.
The tragedy is the latest in the wave of disasters caused by the recent torrential rains in Colorado.
Dwayne Johnson, a high school football coach, was killed. So was his wife, Dawna, who coached track at the same school. Their daughter, Kiowa was a senior at the high school. The two nephews who died were visiting from out of town.
The family was on a popular hiking trail in the shadow of Mount Princeton, about three hours outside Denver. The path is only a mile long and is considered an easy hike.
But the recent downpours that have caused so much flooding across Colorado apparently made the rocks on Mount Princeton unstable. Rescue teams were also in peril.
The victims were buried under boulders the size of cars.
Hiker Adam Rogers made that chilling 911 call. Rogers said, "It was terrifying. I've never seen anything like that. Just the sound alone was really terrifying. There was a huge cracking sound. It sounded like an explosion, and then it came down."
Classmates at Buena Vista High School, where the parents coached and Gracie attended, held a heartbreaking vigil.
YouTube videos show why nature lovers flock to the hiking trails on Mount Princeton. The views from the top are truly spectacular.
Now, tragedy haunts this natural wonder.