Busan, formerly romanized as Pusan and now officially Busan Metropolitan City, is South Korea's second most-populous city after Seoul, with a population of over 3.5 million inhabitants. It is the economic, cultural and educational center of southeastern South Korea, with its port—Korea's busiest and the fifth-busiest in the world —only about 190 kilometers (120 mi) from the Japanese islands of Kyushu and Honshu. The surrounding "Southeast Economic Zone" is South Korea's largest industrial area.