On June 4, 1942, the Battle of Midway, fought between American and Japanese fleets in the Pacific Ocean, began. The Battle of Midway became one of the most important American naval victories of World War II. Midway Island is a fairly isolated atoll, so named because it is midway between North America and Asia in the North Pacific Ocean. Midway was an incredibly strategic location; the Imperial Japanese Navy planned to use it to secure their sphere of influence in the Pacific theater of the war. The Japanese had not lost a naval battle in more than 50 years, and had nearly destroyed the American fleet just six months earlier in a surprise attack on Pearl Harbor, Hawaii. (Pearl Harbor is about 2,100 kilometers (1,300 miles) east of Midway.) American military and intelligence forces worked together to defeat the Japanese. Code-breakers were able to decipher Japanese naval code, allowing American leaders to anticipate Japanese maneuvers. The U.S. Navy was then able to launch a surprise attack on the larger Japanese fleet in the area. The Battle of Midway turned the tide of the war. Japanese and American naval powers were roughly equalized. The war ended three years later, and today the battle is memorialized by such monuments as Chicago Midway International Airport and the Battle of Midway National Memorial.