Oh, the serenity! A walk along this 5.8-km (3.6-mile) stream is almost as good as a spa for clearing one's mind or rethinking a deal. While it's just off Sejongro, one of the busiest boulevards in Seoul, Cheonggyecheon is remarkably quiet because the stream is more than 15 ft. (4.6 m) below street level and feels a little like a dugout. You can take an organized walking tour (register online in advance) or stroll alone. It's very serene with small waterfalls, and nearly two dozen overhead bridges. Don't be surprised if you see more couples here than in New York's Central Park.

• 1. Cheonggyecheon Stream
  Cheonggyecheonro, Jongno-gu, Seoul, South Korea More Info