I want to know the answer to the following question:
Some of the kites remain at what National Historic Site?
All the background I'm provided with is that "The tetrahedral wings were named Cygnet I, II and III, and were flown both unmanned and manned (Cygnet I crashed during a flight carrying Selfridge) in the period from 1907–1912.". Is that enough to answer the question?
Answer: no