Inside the National Building Museum, more than 30 polycarbonate icebergs sit and float in a 12,540-square-foot ocean made of blue net in the building’s great hall. The exhibit, ICEBERGS, was designed by landscape architect James Corner and is the newest addition to the museum’s annual Summer Block Party series. Initially, Corner was intimated by the offer to design the exhibit. “My response was, ‘It’s not a matter of competition,’” said Chase Rynd, executive director of the National Building Museum. “What we’re really interested in is a surprising experience in the great hall.” The exhibit is interactive; including an iceberg slide, educational programming and a kiosk that sells Japanese shaved ice. ICEBERGS opens Saturday, July 2 and runs through Sept. 5. Tickets are $16 for adults and $13 for youth, students and seniors.