The Porsche 911 is one of the most iconic sports cars of all time. Before it was the 911, though, it was called the 901. This 1964 Porsche 901 Cabriolet Prototype was one of just 13 pre-production models produced, and the only one to be built as a drop-top. This exact specimen served as the base for the beloved 911 Targa, is the second oldest surviving 901/911 chassis, and is one of just two pre-production 901s still in existence. As a result, it's not only an exceeding rare piece of Porsche history, but a rare piece of motoring history, period.
Photos: RM Sotheby's