(Photos by Philip J. Hollenback. More here) linked to .

In 1969, Rudolph de Harak designed and the sculptor William Tarr built, a a full-size model of a WWI Sopwith Camel on top of 77 Water Street, a 26 story building, in New York. 

It’s sole purpose is to amuse the inhabitants of surrounding buildings and scyscrapers, most notably the former World Trade Center.

(Thanks, John)