A "station to nowhere" marks the site of a Siberian subway project that never saw the light of day.

Budapest's Communist-era statues, banished to the suburbs.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Once the home of a hermetic monk, this cave now houses a small church.

Inside this Krakow church, an explosion of psychedelic color.

This grubby wall is said to be one of the Earth's esoteric energy centers.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

Tourists who rely on a transit map to find the iconic Beatles location often end up in a far-off neighborhood.

This pub boasts a curious history and may have inspired a Dickens character.

The bridge is a secret gallery of discarded gum that has been transformed into miniature masterpieces.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

The cedar tree in Highgate Cemetery earned its title by accident.

Scattered throughout London are ancient remnants of the city's former bounding wall.

Catacombs turned marketplace.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Europe's official "zero-level," the equator of elevation.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

This unusual elevator doesn’t stop or slow down.

This bird-loving brewery is situated in an old municipal bathhouse, nestled beside a 300-year-old windmill.

These gigantic skeletons tower over visitors and provide insight into the creatures that once ruled over Ireland.

This is the largest cemetery in Ireland and the first cemetery museum in the world.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.