In March 2010, British soldiers were patrolling a street in Afghanistan with a Belgian shepherd named Chocolat. Suddenly, the dog walked ahead of the men and entered an empty shop. His handler knew this meant the dog smelled something dangerous. The soldiers carefully entered the building and discovered a supply of explosives--enough to make more than 10 bombs. Thanks to Chocolat, the weapons had been found before they could do any harm. Chocolat...