Nanjido, formerly used as a landfill site for Seoul and northern Gyeonggi-do, is currently established as an ecological park. After it was rst designated as a land ll on August 3rd, 1977, the site received 110.5 million tons of waste over the next 15 years until the landfill was finally terminated on March 19th, 1993. Within the land- ll’s area of 2.9 km2, two huge waste mountains collectively spanning 1.75 km2 were piled up by the waste. This changed the elevation of Nanjido from 8 m to 98 m. The Seoul government devised a plan to create an ecological park on the closed site, which is now known as the World Cup Park. This park features 5 theme parks: Pyounghwa Park, Haneul Park, Noeul Park, Nanjicheon Park, and Nanji Hangang Park. Noeul Park and Haneul Park are directed located upon former Nanjido land lls #1 and #2. Currently, stabilization work is in progress and is scheduled to continue until 2022. Methane gas and other substances released from the closed landfill are used as heat energy sources for facilities at World Cup Park and Seoul World Cup Stadium.