With only a drop-off between them and the Middle Boulder Creek 1,000 feet below, the Devil’s Slide Trestles hug the side of a mountain in the Colorado Rockies.

According to Atlas Obscura, the Devil’s Slide Trestles were built in 1905 at an elevation of 11,600 feet on the edge of South Boulder Canyon. The train trestles once climbed over the Colorado Gore Range to connect Denver to Winter Park and Salt Lake. Only In Your State reports that the route was part of the old Denver & Salt Lake Railway line, one of the highest standard-gauge, non-cog railroad in the U.S., which ran from 1905 to 1928.

The railroad was dangerous and unnerving, and provided passage for customers of the Denver & Salt Lake Railway. However, the route was abandoned in 1928 when the 6.3-mile Moffat Tunnel opened.

The train tracks were removed in 1938 and the road was opened to automobile traffic in 1955. But the voyage across the high bridges was still disconcerting. After a tunnel collapsed in 1990, the trestles, which had been decaying from almost 100 years of extreme weather, were closed to automobile and pedestrian traffic.

According to Atlas Obscura, the trestles are not safe to cross today. Hikers and mountain bikers can see the trestles from the trail out to the site from either the east or west side of the pass.

According to All Trails, the hike from Rollins Pass Road is 23.2 miles out-and-back, and is considered moderately challenging. It has an elevation gain 2,083 feet, and is popular for fishing, mountain biking, and off-road driving.

Visitors of the area can imagine crossing the bridges, with nothing between them and the 1,000-foot drop to Middle Boulder Creek.

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