Not many cities are nicknamed after their altitudes above sea level, but Denver’s elevation of exactly 5,280 feet makes it unique. It’s the highest major city in America. That distinction is touted by a brass plaque on the steps of the Colorado State Capitol building. (Well, technically, there is more than one, but more on that a little later.)

When you think about it, a mile doesn’t seem like much. It’s the minimum distance people start with when training for a 5K. In high school, coaches test your athletic abilities by recording how fast you can cover the distance, equivalent to making four loops around a football field.

Mile High Marker in DenverYet, it’s a whole different ball game when it comes to altitude. Denver isn’t in but near the mountains. How Denver arrived at its elevation has bested scientists for more than a century. Two years ago, a couple of geologists from the University of Colorado Boulder made national news when they published what is considered to be the best theory: crustal hydration. In layman’s terms, the answer has to do with water. Millions of years ago, water got trapped under the Earth’s crust, creating buoyancy and lift for Denver and its surrounding region. The hypothesis is still being tested.

The mysteries regarding the town’s elevation don’t stop there. In 1909, the first brass plaque was installed on the 15th step of the Capitol’s west side to denote the exact 5,280-foot measurement. The piece was stolen several times, so in 1947 city officials opted for a more permanent solution—inscribing the granite stairs with the words “ONE MILE ABOVE SEA LEVEL.” Fast forward to 1969 when a few engineering students surveyed the site and identified the 18th step as the actual mile-high marker. Another badge was added. The subject came up again in 2003 when—thanks to more advanced technology—a new location was established. Gov. Bill Owens presided over a ceremony during which a third badge was placed two feet below the original marker on the 13th step. This is the one that’s currently recognized as the official 5,280 seal, but the earlier versions also remain.

Those who don’t know the full story like to come up with their own theories. One passerby told us the building sunk and a new badge had to be installed to reflect the new mile-high spot. That doesn’t make much sense considering the newer plaque is also the lowest one. But hey, that’s the thing about mysteries: they draw attention, speculation, fabrication. In spite of—or maybe because of—its murky history, the Capitol’s Mile High Marker is one of the most popular attractions in town—and among the cheapest, too! You can see the markers anytime and tours of the Capitol are available Monday through Friday for free.

4 More Mile-High Spots

Although the Capitol’s mile-high insignia is the best-known story, there are other places around town that also celebrate and make the most of Denver’s lauded elevation.

Coors Field: The 865 purple seats that curve around the upper 300s section aren’t just a spirited decoration, they mark the magic elevation figure. You’ll need binoculars to see much of the action from up there on game day, but on the upside, tickets are pretty cheap.

City Park Mile High Loop: The trail follows the 5,280 contour of City Park for 3.5 miles, so you can get your full 5coors-field-colorado-rockies-fansk training done at one mile above sea level. Along the way, you’ll see markers that point to where the trail hits exactly at a mile high, including one by Denver Zoo and another just past East High School.

High Line Canal Trail: This is another trail that’s great for altitude training. The entire 71-mile path runs from Douglas County past Denver International Airport and sits between 5,410 and 5,542 feet. It’s a touch over a mile, but what’s really cool about this trail is that in its original inception, as an irrigation system in the 1800s, the canal made use of the town’s celebrated height to supply water in an energy-efficient way. It follows the city’s terrain at the highest elevation possible for the water to be driven by gravity, rather than electricity or pumping (that explains the trail’s many twists and turns!) Although it’s mostly used for recreation now, the canal still supplies some farmers in the area.

Denver Museum of Nature & Science: When the The New York Times reported on Gov. Owens’ mile-high marker ceremony, the state’s leader also noted that he had been approached about creating a marker at the museum’s Sky Terrace. He ultimately didn’t, but the elevated view of the city and Rocky Mountains is spectacular.

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