Incheon officially the Incheon Metropolitan City, is South Korea's third or fourth largest metropolis, after Seoul and Busan, and tied with Daegu. As the largest seaport on the west coast and home to the country's largest airport, Incheon International Airport, Incheon is South Korea's most important transport hub. In the 21st century, Incheon has transformed into a global business hub centered around the high-tech and futuristic Songdo International City, which is home to South Korea's tallest building, the 305m supertall Northeast Asia Trade Tower.