This unattributed sculpture in Amsterdam is hiding in plain sight.

For a few short weeks in spring, this hiking path becomes a daffodil paradise.

Browse through a century of this principality's first popular export.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

The Dublin sea wall draws walkers, photographers, and fishing enthusiasts.

One of the oldest lighthouses in the world, this structure was built more than 800 years ago.

This Neolithic passage tomb forms part of a World Heritage Site.

These imposing walls and towers look more like the ruins of a fortress than a monastery.

An ancient neolithic tomb that only sees the sun twice a year.

The ancient tomb acts as a calendar that keeps perfect time.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A small island dotted with old, historic Finnish buildings.

Two well-hidden huts let animal lovers spend the night among the bears, wolves, and other predators of the forest.

Copenhagen's celebrated theme park and gardens.

Climb inside an iron crystal magnified 165 billion times its normal size.

A massive underwater sinkhole made famous by Jacques Cousteau.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

The subtle interplay of fire and water is hard to ignore at this remote Jamaican spring.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

A Cuban artist reclaimed his impoverished neighborhood as a dreamy folk art kingdom.