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.

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.

This illustration shows NASA's Cassini spacecraft about to make one of its dives between Saturn and its innermost rings as part of the mission's grand finale. All ...