Colorado State Capitol - 13th Step

The Colorado State Capitol building in Denver has the 13th step of its main exterior stairway marked and labeled as 'One Mile Above Sea Level', a popular photo spot for residents. The marker has been a local tradition since the early 20th century and encourages visitors and locals to stand on the step for a mile‑high photo. Modern surveys and benchmark adjustments have shown slight variations from exactly one mile, and that discrepancy is sometimes noted in historical discussions about the marker.