Bangchak Under Highway Park transforms 5.2 rai of neglected land beneath an elevated expressway in Bangkok into an inclusive “Park for All.” Once perceived as unsafe and disconnected, the site now brings together sports, play, learning, and community life through futsal and basketball courts, a skatepark, climbing wall, playground, amphitheatre, and Ecological Skywalk. Over 110 trees create a new green lung, improving shade, microclimate, air quality, and biodiversity. The project demonstrates how residual infrastructure space can become a valuable civic and ecological asset.