1963 Aston Martin DP215 – $21,455,000 – RM Sotheby’s
As one of four ‘one-off’ machines originally called ‘project cars’ by Aston Martin – it was manufactured in the ’60s under David Brown’s watch and is the only model of its kind sold as a car at auction. The company held onto this machine in hopes of relaunching it later after closing its racing department in 1963. However, the prototype was sold in 1974.