About 4.5 billion years ago, the Earth accreted. The rest is history.
At the moment, Curiosity on Mars. And my dogs.
"We go out of our course to make ourselves uncomfortable; the cup of life is not bitter enough to our palate, and we distill superfluous poison to put into it, or conjure up hideous things to frighten ourselves at, which would never exist if we did not make them."