from Wikipedia 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.
Busan was the host city of the 2002 Asian Games and APEC 2005 Korea. It was also one of the host cities for the 2002 FIFA World Cup, and is the center for international conventions in Korea. Administratively, it is designated as a Metropolitan City. On November 14, 2005, the city officially announced its bid to host the 2020 Summer Olympics Games.