Lasting six weeks and covering 16,000 miles from London to Mexico City via some of the most varying, tortuous and difficult terrain on three continents, the 1970 World Cup Rally was a unique high-speed event, attracting many serious works teams such as Ford and British Leyland.  Despite the tremendous amounts spent choosing and developing new cars, completing months-long route surveys, and analyzing every detail of diets, oxygen provision, and the number of crew members, out of an entry of more than 100, only 23 cars made it to the finish.  It was, and remains, the toughest rally of all time.