People sometimes ask 98-year-old Ray Lambert if he thinks he's a hero. "I'm not. You know, I'm just, I'm a veteran," he told CBS This Morning. Lambert is one of a dwindling number of D-Day veterans. That fateful World War II battle happened 75 years ago. D-Day refers to the Allied invasion of Normandy, the world's largest invasion by sea. Lambert served as a medic, helping at least 15 wounded men, all while being shot himself.