I found this on the net:
Please park in lot across the street or beside building. Recent construction has erased the road into the site
The Savannah Powder Magazine was built in 1898 and used until 1963 for storing explosive powder, artillery ammunition, and eventually dynamite. It was built when P.W. Meldrim was mayor. The building was designed by Savannah architects, Alfred Eichberg and Hyman Witcover, who are credited separately with Savannah buildings including: City Hall, SCAD's Eichberg Hall, Telfair Hospital, and the Scottish Rite Temple. With a gothic design, The Savannah Powder Magazine is the only municipal powder magazine statewide, possibly the nation. No other similar historic structures exist anywhere in the state outside of military installations such as Fort Pulaski or Fort Jackson.
The 1,400-square-foot, 2-room magazine has survived many controversies and a colorful past. Developers wanted to destroy it. Others talked of converting it to a nightclub. One man aimed to buy and live in it. A homeless man once camped there because he said the natural setting was conducive for communicating with outer space.
Please contact Tommy Holland if you have any interest in obtaining additional information regarding the Savannah Powder Magazine or participating with restoration efforts, call(912)441-0841.