San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

A huge musical instrument played by the ocean.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

The footprint of a frustrated devil in Munich's Cathedral.

This is the oldest Roman-made bridge in the city still existing in its original state.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

Ancient snack bar of the Roman Empire re-opened.

The walls and streets of the ancient city are peppered with penises.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

The celebrated eyesore created by starry-eyed sweethearts.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This museum houses an imposing skeleton army comprised of creatures great and small.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.