Colorado's most impressive human-engineered wonders

Innovative projects that cut through mountains, span chasms, tame rivers and improve recreation access

By Johnny Burkin

Colorado's natural wonders tend to get a lot of attention and rightfully so. But what about its feats of human ingenuity? After all, the state’s diverse and often unforgiving landscape can present many challenges to our modern way of life. Sometimes, that can make building roads, bridges, tunnels, energy infrastructure and dams a task that requires innovative solutions and, yes, a little out-of-the-box thinking. So here’s an ode to some of the Centennial State’s engineering marvels, structures that not only help maintain and improve everyday life, but also open up possibilities for fun and adventure.

A gateway to the Rockies and beyond 

Sometimes the only way is through. In the case of the Eisenhower-Johnson Memorial Tunnel (EJMT), that literally meant going through a mountain, which happens to be part of the Continental Divide. Fully completed in 1979, the nearly 1.7-mile stretch, just 60 miles west of Denver on I-70, has helped facilitate travel between the eastern and western parts of Colorado (and the U.S.), making it easier to access ski areas and numerous other outdoor attractions along the Rocky Mountains.

Although the Eisenhower-Johnson Tunnel was once considered the highest vehicular passage of its kind and reaches an impressive elevation of 11,158 feet, it has since been surpassed by other high-altitude tunnels, especially in China where tunnels have been drilled at more than 15,000 feet. Still, that shouldn’t detract from just how impressive a feat of engineering the EJMT remains to this day. Over the course of its construction, an estimated 1 million cubic yards of material were cleared from each bore and 190,000 cubic yards of concrete were used to line each tunnel. For perspective, that’s 13 times the amount of concrete used to build Empower Field at Mile High, where only 29,000 cubic yards were needed. In addition, features like forced air ventilation and drainage systems were included to ensure safe passage on those slow returns from the hills on Sunday afternoons.

The gorgeous gorge

It’s one of the most beautiful places to experience in all of Colorado. Coincidentally, it is also home to some impressive man-made wonders. For starters, there’s The Royal Gorge Bridge. Built in 1929, it is recognized as the highest suspension bridge in the U.S. and ranks among the highest in the world. Standing just 956 feet above the flowing waters of the Arkansas River, the bridge connects both sides of the Royal Gorge and was designed to provide visitors with stunning views of the landscape. 

Visitors can also take in a different vantage point by hopping aboard the Royal Gorge Route Railroad, another marvel of innovation and design. The railway dates back to the late 1870s and was built to assist mining operations in Leadville. The ride navigates the steep cliffs and difficult terrain of the gorge, passing through Hanging Bridge, a narrow stretch where the train is suspended over the Arkansas and anchored directly into the rock walls along both sides.

The state’s largest man-made reservoir

Grand Lake is Colorado’s largest natural lake. To be sure, the largest overall body of water is the human-created Blue Mesa Reservoir with a maximum capacity of 940,700 acre feet. For comparison, an Olympic-sized swimming pool holds about 2 acre feet of water; Grand Lake holds about 68,000 acre feet. That means, in a head to head, the capacity of  Blue Mesa Reservoir is nearly 14 times larger than that of Grand Lake. That’s a lot of high-quality H2O. Even better, it's available to the public for fishing, boating and all kinds of outdoor fun. While impressive in its own right, the reservoir itself is the byproduct of the Blue Mesa Dam, a key part of the Colorado River Storage Project that has helped regulate the waters of the Gunnison River since 1966. What makes the dam stand out is its carefully planned earth fill construction, which utilizes natural materials to better integrate the structure with its surroundings. Overall, the Blue Mesa Dam stands 390 feet tall and is 785 feet long.

Rails that pierce the divide  

There may be a bit of a theme developing here, but Colorado’s mountain ranges have truly presented distinct obstacles that have pushed the bounds of human innovation. The Moffat Tunnel is a great example. Opened in 1928, the 6.2-mile passageway cuts through the Continental Divide, specifically James Peak, and was built to establish a direct railway between Denver, the Rockies and the West Coast. In fact, Moffat Tunnel shortened the travel distance to the coast by 175 miles, saving freight and passenger lines a pretty penny in operational costs. Still, its construction also came with numerous challenges: like the removal of three billion pounds of rock, the need to build sturdy support systems to prevent cave-ins, and ventilation systems to limit the build up of gases. 

Today, the tunnel continues to be an important part of Colorado’s transportation infrastructure. Passenger liners such as Amtrak's California Zephyr routinely make use of the tunnel and its scenic route. Also, the 56-mile trek from Denver to Winter Park via the Winter Park Express is popular among ski and snowboard aficionados. And for hikers and other sightseers alike, the East Portal Trailhead, located just outside Moffat Tunnel, offers access to a variety of trails, including an enjoyable out and back trip to the Crater Lakes in the James Peak Wilderness area.

The city in a mountain

And the last one is top secret. Unlike the great views and hiking opportunities found at nearby Cheyenne Mountain State Park, this place is not open to the public. Even feeding the giraffes at Cheyenne Mountain Zoo won’t net much intel on this beast.That’s because to get a peek at this marvel one would have to go deep. How deep exactly? Well, 2,000 feet below a solid granite mountain, you know, just far enough to withstand a nuclear blast.

Known as America’s fortress, the Cheyenne Mountain Complex is a testament to the engineering capabilities of the U.S military and it plays an essential role in the country’s national defense operations. Just southwest of Colorado Springs, it once served as the central command for the North American Aerospace Defense Command (NORAD), which is now located at Peterson Space Force Base. The complex, a creation of the Cold War era, functions like a self-contained city, with its own power plants, water systems, food storage and air filtration. Additionally, each of its 15, three-story buildings is built on top of a series of springs in order to protect them from movement. Obviously, given the sensitive nature of the complex, it is only open to authorized personnel. Still, that doesn’t mean everything is completely under wraps. The Peterson Air and Space Museum in Colorado Springs is an excellent stop for anyone looking to take a deeper dive into the history of the Cheyenne Mountain Complex.

In addition to writing and copy editing for Thirst Colorado, Burkin writes screenplays and breaks down the chances of the Denver Broncos and Denver Nuggets returning to championship glory. And he’s been known to bend a few ears with a history lesson.