Busan
Busan Metropolitan City, also known as Pusan, is the largest port city in the Republic of Korea. With a population of about 3.65 million, Busan is also South Korea's second largest metropolis, after Seoul. The most densely built up areas of the city are situated in a number of narrow valleys between the Nakdong River and Suyeong River, with mountains separating some of the various districts.