A sculptor's dream castle turned fantastical ruin.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

The angel of death appears to weep black tears at this grave marker.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

This series of Scottish caves has no clear purpose other than baffling historians.

Also known as "Robin Hood's tree," this tree became a famed location along Hadrian's Wall before it was cut down in an act of vandalism.

This tree was grafted from the actual tree that led Isaac Newton to ponder the theory of gravity.

A meditative space out of a fantasy story.

A famous pilgrimage site that remains hidden in the midst of a city.

This mysterious wheel-cross is the tallest in Britain.

Each winter this underground cave forms a dazzling ice palace.

The ruins of a medieval castle that once belonged to one of the most powerful families in the Netherlands.

This castle played host to the largest great hall found in medieval Central Europe.

This castle ruin in the middle of nowhere is a gem for wildlife enthusiasts.

A little-known castle set in a nature reserve.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

Reportedly the "most handsome" market cross in Scotland.

Inside this reclamation yard is a unique collection of horse-drawn vehicles.

This tablet indicates where the tragic monarch returned to begin her tumultuous downfall.

On a remote island, legend has it that a fiddler and his wife were turned to stone.

148 feet long and in the middle of a verdant forest.

This church combines Christian, Byzantine, and ancient Greek architectural elements.

A lasting testament to the Klondike Gold Rush.

Burial site of a Jewish prophet revered in Iran.