Ammunition Igloo, Military ammunition storage in Golden, Jefferson County, US.

The Ammunition Igloo is a military ammunition storage structure with a curved concrete arch topped by a layer of soil for protection. The walls use rough basalt stone masonry combined with concrete elements, creating a robust bunker-like form designed to withstand stress and contain potential impacts.

Built in 1940 as part of Camp George West during a period of military expansion, this storage facility became part of a standard design for ammunition protection on American military bases. The structure reflects engineering practices that were later adopted across multiple installations nationwide.

This structure reflects how the United States approached military infrastructure in the 1940s, showing practical solutions for protecting dangerous materials. The site demonstrates the engineering priorities of that era and remains a tangible example of how defense needs shaped construction practices.

The structure sits in an industrial area alongside modern office and commercial buildings, accessible from the surrounding parkway. Visitors can view the exterior from the surrounding grounds, though it remains an active historic landmark situated near busy traffic routes.

The name "igloo" was dropped in 2023: the National Renewable Energy Laboratory, on whose site boundary the bunker stands, renamed it internally "Ammunition Bunker" to respect the native cultural meaning of the word. The building is also known as Building 88.