The world is full of swimming holes, but few compare to Samoa’s idyllic To Sua ocean trench.

This secret cemetery where no flag is allowed to fly holds the bodies of American soldiers convicted of heinous crimes during WWII.

This Scottish burial tomb once held hundreds of ancient eagle bones.

These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

This hobbit-y little hot spring may be the oldest spring used by humans in all of Iceland.

This church devoted to Mexico's "dead saint" is a festive celebration of a formerly hidden religious figure.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

A top secret Cold War bunker hidden beneath a Latvian spa facility is now open for tours.

Rising out of a clearing in New Jersey's Pine Barrens is an Aztec-inspired monument to the "Lindbergh of Mexico."

This trio of stone spires claims to be the only preserved medieval execution site in Europe.

A small square plaque marks a failed assassination attempt that could have changed history.