Cheongyecheon is a beautiful creek that was restored after being “buried” under a concrete highway for approximately 30 years or so. It was restored in 2005 and is a great example of beautiful city design. You can take a nice leisurely stroll along this creek which is especially pleasant during a summer night.
This was one of my favorite areas to go at night as you can go for a nice walk and clear your head. There are also occasional events all over the place, such as fashion shows, lantern festivals, movies, and etc. You can take a nice rest there with your feet in the water as well!
Much of the action happens at the plaza, where the creek starts. You can access this place at the 시청역 (City Hall Station) on the 2nd (green) line. It is one of the most beautiful parts of the creek as well. This area is very close to 세종로 (Sejong-ro), where you can see the giant statue of King Sejong and walk towards 경복궁 (Gyeongbokgung Palace), which is probably the most famous palace in Korea.