Earth Day
Last year I posted a bunch of images of the Earth. This year I'm just posting the one. It was taken by the Voyager 1 space probe on February 14, 1990 from a distance of four billion miles, and I found it at JPL's Planetary Photojournal.
It's good once in a while to remember that, big as it seems, this is a pretty small neighborhood we live in.
You may also be interested in seeing that image as part of a larger mosaic, in which the Earth is just a tiny mote in the glare of the sun. I love these images.