This site was a naval weapons test facility from World War II to the early 1990s. It was established by Caltech, which was developing weapons for the Navy at its Naval Ordnance Test Station, China Lake, near Ridgecrest. Because there is no water to speak of at China Lake, Caltech opened this substation near the dam at the Morris Reservoir, in the San Gabriel Mountains, north of Azusa. This site was used especially for the development of submarine-based warfare systems, including torpedoes, bombs, and submarine-launched missiles like the Polaris rocket, the first ballistic missile that could be launched from submerged submarines. Most of the buildings at the test site have been removed, and the site is being restored to a naturalistic state.