The Gossamer Albatross
was the first ever successful human-powered
aircraft to cross the English Channel
; which it managed in 2 hours and 49 minutes.
The aircraft was sponsored by DuPont and designed by Dr. Paul MacCready.
It was constructed of incredibly light kevlar and aluminum, and covered with mylar film. The entire aircraft weighed just 30 kilograms (about 66 pounds), but had a wingspan of over 30 meters (98.4 feet)!
The pilot, Bryan Allen was a professional cyclist and hence had an excellent power/weight ratio, which made the whole thing possible. The whole time he was in the air he was pumping out around 400 watts.