Gunsan is a west-coast port in North Jeolla, about an hour from Jeonju. It is not pretty in the usual Korean city way, but it has one of the country's clearest collections of early-20th-century colonial buildings: old banks, warehouses, a Japanese-style temple, and streets that still carry the mood of a trading port.
The city was important under Japanese rule and came through the Korean War with much of that fabric intact. That makes Gunsan a good stop if you want to understand Korea's modern history outside the big museums of Seoul. The modern history quarter around Jangmi-dong is compact enough to walk, with the museum, art spaces, and bakery culture all close together.
Gunsan also has a second identity offshore. The Gogunsan islands and Seonyudo give the city a summer beach and cycling escape, linked by bridges and backed by low hills. Come for the modern-history walk, then add the islands if the weather is kind.