Building # 1 is the oldest brick structure in Key West built by the U.S. Navy as a Coal Depot and Storehouse. It coordinated refueling steamships and was a vital source of coal from 1856 â€“ 1900. During the Civil War, the Unionâ€™s West Indies Blockade Squadron was headquartered here. The blockade shortened the war and saved many lives on both sides of the conflict. In 1932 the 7th Lighthouse District occupied the structure. In 1939, the building became the U.S .Coast Guard Headquarters.