Seoul is the capital of South Korea. The city center lies in the Cheonggyecheon valley through which the stream flowing into the Han River flows. Formerly, it was located under the highway, however, at the beginning of the 21st century it was rediscovered and the area along the watercourse was transformed into an eye-friendly city park. The creation of green areas in the heart of a bustling modern city turned out to be one of the most successful projects of revitalization in Seoul. Currently, the 11-kilometer stream is one of the tourist attractions of the Korean capital, especially during the Lantern Festival organized in November.