NASA first wowed us during the Apollo missions with their blue marble photo taken in 1972 by Apollo 17 astronauts. They've been re-releasing their "blue marble" photos recently, taken in high definition by satellites around the earth and stitched together by computers to show as little cloud cover as possible. Here's one of Africa that you should check out.
(Buy a blue marble photo here.)
Note that Africa is 20 percent of the Earth's land mass and hosts 877 million people within its shores. Meanwhile North America only hosts about 500 million people. Its these kind of photos that show that this planet is basically the only eco-system we can currently live in.
(Learn about Africa with this book.)