Cheonggyecheon is a 10.9-kilometer-long (6.8 mi) linear park in the Central Business District (CBD) of South Korea’s capital city. The Cheonggye Expressway was torn down in 2003 to make way for this urban revitalization project, including the natural stream sourced from the Suseongdong Valley. The project was finished in two years, costing 386 billion won…