hips such as Yamashiro, and aircraft carriers such as Hiry? and Sh?kaku. Smaller warships were constructed at the privately owned Uraga Dock Company. Yokosuka Naval District was the home port of the IJN 1st Fleet.
The Great Kant? earthquake of 1923 caused severe damage to Yokosuka. The city continued to expand in 1933 with the annexation of neighboring Kinugasa Village and Taura Town in 1933 and Kurihama Village in 1937. In 1943, the city also annexed the neighboring towns and villages of Uraga, Kitashimoura, Okusu, Nagai and Takeyama, as well as Zushi.
During World War II, Yokosuka was bombed on April 18, 1942 by American B-25 bombers in the Doolittle Raid with little damage as a retaliation to the attack on Pearl Harbor. Aside from minor sporadic tactical air raids by United States Navy aircraft, it was not bombed again during the war; however, from 1938 to 1945 more than 260 caves in more than 20 separate tunnel/cave networks were built throughout the area, with at least 27 kilometers of known tunnels within the grounds of Yokosuka Naval Base. Many more tunnels are scattered throughout the surrounding areas. During the war, these tunnels and caves provided areas in which work could be done in secrecy, safe from air attacks. A 500-bed hospital, a large electrical power generating facility, and a midget submarine factory and warehouse were among the many facilities built. American occupation forces landed at Yokosuka on August 30, 1945 after the surrender of Japan, and the naval base has been used by the US Navy since that time.
From the 1950s, United States Fleet Activities Yokosuka has been home port for the United States Seventh Fleet, and played a critical support role in the Korean War and the Vietnam War. Yokosuka was the site of many anti-war protests during the late 1960s and 1970s. The nuclear powered USS George Washington is currently based at Yokosuka, the first time a U.S. nuclear powered ship has been permanently based in Japan
