What event marked the beginning of the Korean War?

The Korean War began when North Korea launched an invasion into South Korea on June 25, 1950. This aggressive maneuver initiated a full-scale conflict between the two nations, leading to a response from the United States and other member nations of the United Nations, who sought to support South Korea. The invasion was a pivotal event because it not only marked the official outbreak of hostilities but also underscored the geopolitical tensions of the Cold War era, as it was seen as an attempt by communist North Korea to expand its influence over the democratic South.

The other events mentioned do not directly pertain to the start of the Korean War. The Geneva Accords were related to the resolution of conflicts in Indochina and are not tied to the events in Korea. The establishment of the 38th parallel was a demarcation line that existed post-World War II, but it was the invasion that triggered the war, not the line itself. The fall of Saigon happened much later in 1975 and relates to the Vietnam War, making it unrelated to the starting point of the Korean conflict.