An curved arrow pointing right. NASA's Cassini spacecraft plunged into Saturn's atmosphere on September 15, marking an end to its mission to study the ringed planet and its many, mysterious moons.

Twenty years ago, a rocket launched from Cape Canaveral in Florida on a billion mile trek to Saturn. The photos the probe took revealed some astonishing things about Saturn, its rings and moons.

At 5 am ET on Wednesday, NASA will fly its $3.26 billion Cassini spacecraft where no spacecraft has flown before — in the deepest region of Saturn's rings between the planet and its inner-most ring.