What is the fine-grained topic of the following text: In the fall of 1970, when Piene was in town to dedicate the Capitol chandeliers, the museum hosted an exhibition—and a “happening.” On Saturday, September 19, Piene and a group of volunteers created Sky Lei, an inflatable flower made from 2,500 feet of polyethylene tubing that flew 1,000 feet over Kapi‘olani Park. Only return the topic.
Piene's Sky Lei Inflatable Art Exhibition in 1970