Official Word:

The première of the Model 180 (W 120) in 1953, today lovingly referred to as the "Pontoon Mercedes" (or the "Roundie"), was a technical and aesthetic milestone in the history of the passenger cars from Mercedes-Benz. The intermediate saloon was the first car from the Stuttgart-based brand to feature a unibody and at the same time the first whose bodywork was designed in the form of a pontoon. The W 120 was a trendsetting predecessor of...Read.