The Aleutian World War II National Historic Area is a U.S. National Historic Site on Amaknak Island in the Aleutian Island Chain of Alaska. It offers visitors a glimpse of both natural and cultural history, and traces the historic footprints of the U.S. Army Base, Fort Schwatka, located at the Ulakta Head on Mount Ballyhoo. The fort, 800 miles west of Anchorage, the nearest large urban center, was one of four coastal defense posts built to protect Dutch Harbor (crucial back door to the United States) during World War II; Fort Schwatka is also the highest coastal battery ever constructed in the United States. The other Army coastal defense facilities were Fort Mears, Fort Learnard, and Fort Brumback. Engineers designed the concrete observation posts and command stations to withstand earthquakes and 100 mph winds. Although today, many of the bunkers and wooden structures of Fort Schwatka have collapsed, the gun mounts and lookouts are among the most intact in the country.