War broke out in Korea early on the morning of June 25, 1950. Korea—long known as the "Land of the Morning Calm"—surrendered its tranquility to the Communist forces of North Korea. At 4:00 a.m., amid torrential rains and the thunder of big guns, some 90,000 North Korean troops poured across the 38th parallel separating the North and South. Only about one-third of South Korea's army of 95,000 troops stood forth to meet the surprise attack. The North Koreans easily overwhelmed their southern neighbors. Seoul, the South Korean capital, fell to the invaders in three days. The United States, under the banner of the United Nations, rushed military forces to the defense of South Korea's embattled army. But the North Korean aggressors pressed relentlessly southward. By August 4, the UN defenders clung desperately to a tiny foothold at the southern tip of the peninsula known as the Pusan Perimeter—hoping for reinforcements or a miracle.