An ancient octagonal weather station named for the eight Greek gods of wind.

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

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

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

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

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

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

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

This spectacular public market has got meat, fish, vegetables, baked goods, and enough kielbasa for a lifetime.

Why have you never heard of the second most popular tourist site in New York?

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

The trials and tribulations of marking Poe's grave.

A six-foot pair of socks hangs from a drawer of the world's largest bureau.

Inspired by a foil-wrapped potato, (seriously) the Markel Building has been deemed one of the 10 ugliest buildings in the world.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

This labyrinthine resting place of Black American leaders has been reclaimed by nature.

Under a playground is a little-known sealed train tunnel that likely contains the bodies of workers trapped by cave-ins.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

World's first "penitentiary," meant to be humane, drove men insane.

A Nessie-like monster supposedly lurks in this lake.

Practice your Dirty Dancing lifts in the manmade lake where Johnny Castle himself did.