As the most conspicuous stone fortress protecting Portland Harbor, Fort Gorges is a landmark visible from much of Casco Bay, which is exactly why it was built on this rocky outcropping a short distance from Peaks and Little Diamond Islands and the mainland itself. The fort could fire more than a dozen cannons on attackers coming from any possible sea route, but was never used in active battle. Technological advancements in artillery during the Civil War rendered it too vulnerable to be useful. The fort did serve as a storage facility for the army during World War II, when underwater mines, electromagnetic sensing cables, and other systems were used to help protect Portland and Casco Bay from German attack. Remember, Portland was home to a large shipyard during WWII and was the start of a pipeline that supplies oil to Montreal and eastern Canada, so the region was of high strategic importance even in more modern conflicts.