Otto Wilhelm Rudolf Caracciola (30 January 1901 – 28 September 1959), more commonly Rudolf Caracciola, was a racing driver from Remagen, Germany. He won the European Drivers' Championship, the pre-1950 equivalent of the modern Formula One World Championship, an unsurpassed three times. He also won the European Hillclimbing Championship three times – twice in sports cars, and once in Grand Prix cars. Caracciola raced for Mercedes-Benz during their original dominating Silver Arrows period, named after the silver colour of the cars, and set speed records for the firm. He was affectionately dubbed Karratsch by the German public, and was known by the title of Regenmeister, or "Rainmaster", for his prowess in wet conditions.
Hat tip to Bernhard Leimbrock!