Fort Charles is the oldest of the six forts that once defended Port Royal and the only one still standing in any complete form. The British built it in 1655 immediately after taking the island from the Spanish, originally calling it Fort Cromwell. It was a vital piece of the chain of harbour defences that protected the buccaneers, naval ships, and merchantmen anchored in Kingston Harbour.
The fort survived the 1692 earthquake, the 1907 earthquake, and several hurricanes. Inside the walls is a small maritime museum with cannons, anchors, ship models, and material recovered from the underwater excavations of the sunken city. The ramparts give a panoramic view across the harbour to Kingston and out to the Caribbean.