What on Earth? investigates mysteries from strange geological occurrences to weird man-made structures. Every day, the eyes in the sky uncover new mysterious phenomena, and some defy easy explanation. Satellites that speed through space at 17,000 miles per hour have the potential to unveil all sorts of hidden wonders. Equipped with high-tech optics and radar, they reveal unseen worlds. Bizarre images can raise questions about the Garden of Eden, El Dorado, ancient cultures and hidden bases.