They are usually intended for use in public places, and intended for the short- or long-term private use of individuals for storing clothing or other personal items. Users may rent a locker for a single use or for a period of time for repeated use. Some lockers are offered as a free service to people partaking of certain activities that require the safekeeping of personal items.
Locker doors usually have some kind of ventilation to provide for the flow of air to aid in cleanliness. These vents usually take the form of a series of horizontal angled slats at the top and bottom of the door, although sometimes parallel rows of small square or rectangular holes are found instead, running up and down the door. Less often, the side or rear walls may also have similar ventilation.
Bicycle lockers are usually in outdoor locations near railway stations and the like where people may want to store bicycles securely. They are often banked together, with individual lockers shaped like an isosceles triangle for efficient and compact storage of a bicycle. This triangular shape permits the lockers to be grouped either in a radial pattern (with the sharpest points of the lockers together), or in a row in alternating orientations.
Some schools in the United States have been reported to have abolished the use of lockers. Security concerns are cited as the reason for this, with the concern being that lockers may be used to store contraband items such as weapons or drugs or pornographic material.[1] There has been some controversy over in what circumstances school authorities or law-enforcement officials are permitted to search lockers, with or without informing the users, or with or without the users being present at the time of the search, and it has been considered a civil liberties issue, particularly in the U.S.
There is a luggage storage service a short one minute walk from Union Station in downtown Denver - LUGDEN. You can make a reservation online -, call - (303) 747-5600, or show up as a walk-in. They offer hourly, day, overnight and weekly bag storage. Great place to store your luggage if you're on a layover from Denver International Airport, or going to a concert, or headed to a Rockies game at Coors field and want to enjoy yourself without having to lug your bags around.

Denver Lockers