Gladiators once walked this ancient, subterranean passage.

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

The remains of the medieval wall that once surrounded Paris with ties to the construction of the Louvre.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

A surrealist timepiece by the artist of melting clocks.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

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

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

The world's oldest operational public pier railway has shuttled seagoing commuters from ship to shore since 1909.

In 1977, an eccentric book lover formed a micronation for book lovers.

This bridge is the first to be made entirely from iron, but designed like it was still made of wood.

This charming railway is one of the oldest and steepest funiculars in England.

A 13th-century fortified manor house that was once sieged during the English Civil War.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

The tomb of a hard traveling saint is constantly covered in shoes as offerings to heal disabled youth.

Want to properly offend a king? Sculpt a giant hill figure in chalk of him riding out of town.

Six neolithic sandstone boulders remaining from a dolmen.

This modest relic, with rich history as a strategic fort through multiple eras.

This gate served as a small lock-up jail in the 14th century.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

Where Agatha Christie mysteriously disappeared in 1926.

The last fully working Victorian Turkish bath in England.

This innovative steam machine was no doubt the most famous of the pioneer locomotives.