Lo inexplicable

Humans have explored outer space and the ocean's depths but have barely scratched the Earth's surface. What lies beneath, and what can it tell us?

Scientists continue to ponder if time travel is theoretically possible. But if it has already occurred, what would the implications be for our reality?

Modern archaeologists investigate the secrets of the world's ancient ruins and theorize how these incredible structures came into existence.

Vikings were infamous fighters of their time, but historians continue to discover that their society held more than bloodthirsty warriors of legend.

There have been fewer than 50 presidents of the United States of America — but even they are the subjects of peculiar tales that defy easy explanation.

Despite incredible advances in medical science, there remain many illnesses and afflictions for which scientists do not know the cause, let alone a cure.

Ancient artifacts and mysterious objects continue to confound curious minds about their origins and what secrets they may hold.

From intelligence agents to puzzle fans, cracking secret codes is a fascination for many. But there are several ancient ciphers that remain unsolved.

One of the most-documented conflicts in history, WWII spawned intriguing and inexplicable mysteries. But are those stories based in fact or fiction?

Some of mythology's most terrifying creatures may have a basis in truth, but what can those legends tell us about the monsters lurking in our world?