On December 9, 1979, an international team of scientists verified the success of the World Health Organization's efforts to eradicate smallpox, a deadly disease that had killed billions (an estimated 300–500 million during the 20th century alone) since 10,000 BC. In all of human history, smallpox remains the only infectious disease affecting humans to have been eradicated. It was only wiped off the face of the Earth after a concerted effort by all of the world's governments to end this scourge. Think about it: amazing what mankind can accomplish when we all cooperate for the common good. And equally amazing what results when we don't.