Colorado's State Capitol makes Denver's elevation claim official, visible to you and to anyone looking at the skyline. The Colorado State Capitol was begun in 1886 and completed in 1908, modeled on the United States Capitol with a dome rising 272 feet above the ground. That dome was originally covered in copper, then gilded with 200 ounces of gold leaf in 1908 — donated by Colorado miners as tribute to the industry that built the state — and renewed three times since.
On the west steps, the thirteenth step from the bottom is marked ONE MILE ABOVE SEA LEVEL, a measurement revised twice as more precise surveying improved. Inside, the rotunda is lined with rose onyx wainscoting from a quarry in Beulah, Colorado — the world's only known deposit of that particular stone. The entire deposit was used for this building, which means what you see here is all there is anywhere on earth.
Look up into the dome from the interior; the stained glass windows are original. This building has been the seat of Colorado government for more than a century, presiding over a state that went from mining camp to metropolis in a single human lifetime.