Denver, Colorado has a reputation as the mile-high city. And it’s true. The elevation of the city is one mile above sea level.
Note to purists: Elevation varies block by block. Official marker is located on one of the State Capital steps. So I’m sure you could find neighborhood both higher and lower than exactly one mile.
When I visited the capital building — my companions were two male teens. (Yes, it made for an interesting vacation.) Near the end of the self-tour, we were at the base of steps going up to an observation deck at the base of the dome. This is a time to swallow any hesitation and take the opportunity.