Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

One of two electrical towers in Germany that have a pathway constructed through the tower's legs.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

Paris' linguistic guide to the international language of, yes, love.

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

An honorary saint of the people, Maria Adelaide became an incorrupt corpse, the clothes intact, exhaling “a strong scent of roses.”

Picturesque intersection of witchcraft and ancient Christianity.

The stunning interior of this Gothic church is covered in ornate gold details.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

A hidden three-foot-wide house separates these two regal churches.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

An early work of the architect Álvaro Siza Vieira, these swimming pools blend into the beach.

Iron Age runes and ruins hide in plain sight along this Portuguese beach.

"Satisfying" is a good way to describe these beautifully aligned rows of Spanish mills.

This abandoned naval battery stood at the ready as recently as the 1980s.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

Thanks to an acoustic anomaly, this unassuming stone bench has heard one hundred years of secrets.

The oldest Roman lighthouse still in use.

Giant granite sculptures representing family on the northern coast of Spain.