Apollo held up the 20th century's most amazing mirror, when we gazed at ourselves, our blue water-planet, as Copernicus could only imagine; but, in the end, no show-and-tell could save us from ourselves.
So, today, we must have "Earth Day" (and personally remember Jacques Cousteau, who tried to save the oceans, as well as those who are trying to "save" the air...).
NASA: view of earth from Apollo mission xx
Jordis Unga: