Grand Prix of the Nations at the Nürburgring, July 14, 1929. The Mercedes-Benz team on Mercedes-Benz SSK sports cars at the start: Rudolf Caracciola / co-driver Heinrich Kühnle (starting number 2). Georg Kimpel / co-driver Eugen Salzer (starting number 4). Willy Rosenstein / Adolf Rosenberg (starting number 12) (from left).