The UnXplained With William Shatner

A look at whether time travel has already occurred, on purpose or by accident, and scientists who believe it is theoretically possible.

Age-old mysterious ruins stand as silent sentinels from the past, with their true history seemingly erased by time; modern archaeology attempts to unravel the enigma of how and why the ancient structures were built.

There are many bizarre tales involving U.S. presidents that defy explanation and are still shrouded in mystery.

From mysterious wounds that appear for no apparent reason, to a peculiar madness that compels people to dance themselves to death; looking at bizarre afflictions.

There are many puzzling artifacts from around the world that challenge everything known about the technological capabilities of distant ancestors; some ancient objects are so mysterious they've spawned endless debate and theories.

There's nothing more fascinating than a code that can't be cracked. For centuries, mankind has devised ingenious ways to hide valuable information--using everything from enigmatic puzzles, to complex ciphers and secret symbols. If history's unbreakable codes can be deciphered...could we unlock answers to some of the greatest mysteries of both the past and present?