Two years and five days ago, NASA’s rover Curiosity landed with a dusty thunk in a crater on Mars. One of the first things the six-wheeled, nuclear-powered rover did — after its 8-month journey and daring descent to the red planet’s surface — was send a sort-of selfie back home.

Then it got to work, exploring the insides of Gale Crater and sniffing around for signs that Mars was once capable of hosting life. It found them. Among Curiosity’s early discoveries is the fact that it landed in a stream bed — as narrator Felicia Day says in the newly released video above, “Billions of years ago, you could have