From 1921 issues of Flying (click to enlarge):
Designed as a cross between a houseboat and plane, the Caproni Triplane flying boat was one of the largest seaplanes ever built. The plane used three sets of triplane wings taken from World War I bombers attached to a 100-passenger flying boat hull. Powered by eight 400-hp engines, the plan was to carry 100 passengers as well as six pilots and flight engineers. However, on the plane’s second flight in 1921, it crashed into a lake, killing both pilots, which led designers to scrap the design.
Still, it must have been something to see in person!