Scattered throughout the Garapan area are three Japanese defensive positions built to protect the island from a U.S. amphibious invasion during World War II. These three fortifications, (from north to south) include: a small, rock and concrete bunker built to house a machine gun located at the western end of American Memorial Park; a larger concrete blockhouse on the beach at the Hyatt Hotel which enclosed a 20 mm cannon; and a medium-sized bunker just to the south of the Garapan Dock which probably protected a heavy machine gun. Japanese defensive doctrine at the time of the Marianas Campaign called for the enemy to be defeated at the beaches and thrown back into the sea. Accordingly, priority was given to constructing coastal defenses rather than at inland locations. Most of the concrete fortifications were built by the Japanese in the last few months before the American invasion when construction materials were in short supply. Some fortifications lacked weapons at the time of the invasion. Following the loss of the Marianas, Japanese commanders switched to a defense “in-depth” which was employed during the battles of Peleliu, Iwo Jima, and Okinawa.