I have taken several MOOCs with Sachs and another expert. He is nicknamed the world's professor because these courses attract activists and pros as well as frightened, bright students - from all over the world. You can end up with both book knowledge, taught mostly in gorgeous video of the world's people and nature, and a network of friends spanning the globe. We have tough, complex work to do in order to save our SPECIES. UNDERSTAND how the United Nations has led the effort ever since JFK said we'd go to the moon "and do the other things" so hard. We've been looking down at Earth, seeing the beauty and the damage. LEARN HOW TO help!