Denver is known as the Mile High City, but you have to stand on the steps of the Capitol to properly reach those heights—the rest of the city comes up just a little bit short.

Even at the State Capitol, achieving precisely 5,280 feet in elevation has been a bit finicky. Over the years, no fewer than three of the granite steps leading to the main entrance have been identified as the golden plateau.

The 15th step is engraved with the words “One Mile Above Sea Level.” It held this distinction from 1909 to 1969, when a group of students from Colorado State University remeasured. Their calculations put a mile high on the 18th step, which prompted the installation of a bronze marker. In 2003, the elevation was measured again. This time, the researchers identified the 13th step as the correct benchmark. A brass medallion engraved with the silhouette of the Rocky Mountains was formally installed in a ceremony later that year (the governor gave the keynote).

The difference between the 15th and 18th step is 3.03 feet and the discrepancy has to do with an update to the North American Vertical Datum (NAVD), which is the standard control of orthometric height in the United States. The 1969 measurements had been done with a previous standard, not the NAVD of 1988, which remains in use today.

Whether the mile-high marker is due for another move remains unknown, and visitors are welcome to attempt their own measurements and place their bets. But the best thing a visitor could do would be to turn away from the stairs and take in the view of the mountain range rising behind them. Whether on the 8th step or the 20th step—a little too high or a little too low—it’s not too shabby up there.