Cheonggyecheon is a historic stream in Seoul, South Korea, that was once a natural waterway but was covered by an elevated highway for decades. In a landmark urban renewal project from 2003 to 2005, the highway was demolished and the stream was restored. Today, Cheonggyecheon is a popular 11-kilometer-long urban oasis that flows through downtown Seoul. It is a symbol of sustainable urban development and a key recreational space for both locals and tourists. The stream features pedestrian walkways, art installations, and is a venue for various cultural festivals throughout the year, like the Seoul Lantern Festival.