The Korean War was a conflict fought on Earth during the mid 20th century in Korea. It began as a civil war between North Korea, which was supported by the Soviet Union and later China, and South Korea, which was supported by the United States of America and its allies.
In 2376, Elias Vaughn had a second orb experience with a Bajoran Orb. In this experience, Vaughn became Eli Underwood, a veteran of the Korean War who was present when the allied forces retook the capital city of Seoul. (DS9 novel: Unity)