Sometimes when mankind appears to be at its worst, it gets a welcome shot of medicine to add perspective and make our human-sized conflicts seem slightly less burdensome. Such a moment occurred July 20, 1969, 46 years ago Monday, when American astronauts Neil Armstrong and Buzz Aldrin became the first humans to set foot on the moon. The historic mission capped a decade that saw the nation and world divided by war and social upheaval.