Photo: "Magazine Storage"

At the Southern tip of the former Mare Island Naval Shipyard groupings of former magazine buildings still remain today even though the shipyard has been decommissioned for nearly 20 years. These buildings once stored a variety of ammunition for land and sea weaponry. 

I've been told the walls of these buildings were constructed of concrete and the roofs of a metal material, so that during an accidental explosion, the blast would move vertically instead of horizontally.