The ruined doorway is a portal to the building's turbulent and torturous past.

Legend says this sacred tree was a gift from goddess Athena.

Ancient Greek oracle of the dead.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

This legendary city has been a tourist attraction for centuries.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The hallucinogenic center of the ancient world.

This verdant, tree-lined Reykjavik graveyard is both enchanting and eerie.

A sulfuric martian landscape that looks far better than it smells.

Three columns of volcanic rock shoot out of the ocean.

This tiny museum's sizable collection is jammed into a former underground public toilet.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

An encyclopedic collection of mammal penises.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Medicinal spa created with the discharge from a geothermal energy plant.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

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