Second largest city is Busan with a population of approximately 3.6 million. The population of the metropolitan area, including the adjacent cities of Gimhae and Yangsan, is approximately 4.6 million.

Busan is a beautiful city full of great seafood delights. Hyundae beach is a favorite place for many Koreans and has white sands and many nearby hotels. The language has a southern accent, and they use some words not commonly used in the Northern Provinces. Daegu is the 3rd largest city and is famous for apples. Gunsan is on the West coast and is a seaport and manufacturing center with an American Air Base close by.

More Info: en.wikipedia.org