Incheon, South Korea's third largest city, 28 km west of Seoul, is the gateway of central cities to Incheon port, the most famous modern Incheon international airport in the Northeast. ASIAN. With strong terrain and investment, Incheon promises to be the central city of the world in the 21st century. Incheon is also famous for its many tourist landscapes, to Incheon, visitors can visit large islands. small, ebb tide, beautiful parks and ancient ruins.