Ferrari and Porsche proved why they are legend. But Detroiters Penske and Cadillac got very close to 24 Hour Le Mans glory.

With GM President Mark Reuss at the wheel, Cadillac has gone international to take on its European competition on the track — and in the showroom.

As day turned to night, and back again, the 93rd edition of the 24 Hours of Le Mans delivered a gripping demonstration of ...