On this day (14 Oct) 47 years ago - one of the most expensive cars ever built, the US Presidential 1969 Lincoln Convertible Executive, was delivered to the US Secret Service. It was 21 ft 6 inches in length, with a 13 feet 4 inch wheelbase. Including 2 tons of armour plating, it weighed 5.35 tons. The estimated cost of research, development and manufacture was $500,000. Even if all four tyres were shot out, it could travel at 50 mph on inner rubber-edged steel discs.