Mercedes 219 (1956-1959) from "Ponton" family. The nickname comes from the German word for "pontoon" and refers to one definition of pontoon fenders — and a postwar styling trend, subsequently called ponton styling. 6-cylinder-inline engine (four-stroke), front-mounted.
The Ponton was Daimler-Benz's first totally new Mercedes-Benz series of passenger vehicles produced after World War II. In July 1953, the cars replaced the pre-war-designed Type 170 series and were the bulk of the automaker's production through 1959, though some models lasted through 1962. 6-cylinder models, like 219, were more exclusive and of higher price.
Assembly lines. Photo from www.mbzponton.org