Corregidor functions as an open-air WWII museum and national park — a place where the jungle has been slowly reclaiming what was once one of the most heavily fortified islands in Asia. Most visitors arrive on a day trip from Manila and are guided around on a tramvia circuit that stops at the main sites: the Malinta Tunnel, the Pacific War Memorial and officers' barracks ruins at Topside, the coastal gun batteries, and the Spanish colonial lighthouse. The circuit covers the essentials efficiently, and the guides provide the historical context that makes sense of the ruins.