150 years ago today The New-York Times headlined some remarkable technology. The world’s largest ironclad was launched three months after the Civil War ended, and some people imagined trains running up in the air over Broadway.
The USS Dunderberg was never accepted by the United States Navy. France bought the ship in 1867 to sort of beat Prussia to the punch. The renamed Rochambeau never saw action in the Franco-Prussian War and was scrapped in 1874.

“United States iron-clad screw ram “Dunderberg”–Designed and constructed by Wm. H. Webb / sketched and drawn on stone by Parsons ; lithographed and published by Endicott & Co., New York. ” (c.1867, Library of Congress)