The National Building Museum had a huge playground this summer. It was inside the museum’s large hall. Children and adults could climb, build, and rest. There were wood walls, sand, balls, and hammocks. Hammocks are beds that swing. (nbm.org) Visitors could also make things from simple parts. For example, a child could build a small house. A parent could help. The hall felt like a fun park. People learned by using their hands. They also played together.