Cheonggyesan (Seoul and Gyeonggi)
Cheonggyesan (Korean: 청계산) is a mountain in South Korea. It extends over Seocho District, Seoul and the cities of Gwacheon, Uiwang, and Seongnam in Gyeonggi Province.
Source: Wikipedia — Cheonggyesan (Seoul and Gyeonggi) (CC BY-SA 4.0)