Suwon

A popular day trip out of Seoul, sprawling Suwon (수원) is the largest city in Gyeonggi-do province, with World Heritage–listed fortifications still looping around its heart. Suwon almost became the country's capital in the 18th century, when Joseon dynasty ruler King Jeongjo built the 3.5-mile-long walls (5.7km) in 1794–96 ahead of moving the royal court south. However, the king died, power remained in Seoul, and Suwon ended up with one hell of a tourist sight. The city is located around 18.5 miles (30km) south of Seoul.