Begun in 1787, Fort Charlotte is the largest of Nassau's three major defense buildings, built with plenty of dungeons. It used to command the western harbor. Named after King George III's consort, it was built by Gov. Lord Dunmore, who was also the last royal governor of New York and Virginia. Its 42 cannons (only seven remain on-site) never fired a shot -- at least, not at an invader. Within the complex are underground passages, which can be viewed on a free tour (guides are very happy to accept a tip).