Busan (Officially Busan Metropolitan City and formerly spelled Pusan) is South Korea's second largest metropolis after Seoul, with a population of around 3.6 million. The Metropolitan area (includes adjacent cities of Gimhae and Yangsan) population is 4,399,515 as of 2010. It is the largest port city in South Korea and the world's fifth busiest seaports by cargo tonnage. The city is located on the southeasternmost tip of the Korean peninsula. 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 districts. Administratively, it is designated as a Metropolitan City. The Busan metropolitan area is divided into 15 major administrative districts and a single county.

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 a center for international conventions in Korea. On November 14, 2005, the city officially announced its bid to host the 2020 Summer Olympics Games. After Pyeongchang's successful bid for the 2018 Winter Olympics, the city is considering its bid to host the 2024 or 2028 Summer Olympics.

Busan is home to the world's largest department store, the Shinsegae Centum City.