This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

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

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Perhaps the most spectacular grotto along the Algarve coastline.

This small chapel is built of human bones and decorated with a golden skeleton.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

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

Real bones which are said to have belonged to a Polish dragon.

Warsaw's fantastically preserved gasworks...almost.

This enormous 32-foot painting depicts Poland's greatest medieval battle in glorious detail.

This antique thermometer honors the creator of the first universal temperature scale.

A mysterious emblem tucked in an small alleyway is actually the coat of arms of a heroic medieval family.

The final resting place of more than 200,000 people, this is one of the largest cemeteries in Europe.

Longest road tunnel in the world features an air treatment plant and the illusion of daylight.

This handsomely carved wooden church is more than 800 years old.

This windmill has been grinding pigments for traditional paints for more than 200 years.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

A poignant museum dedicated to the history of the Dutch resistance against Nazi occupation

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

Cemetery honors Americans who died during WWII and is the resting place of Gen. George S. Patton.

This small chapel built into rock is the oldest place of worship in Luxembourg.

Liechtenstein's royal family calls this medieval alpine castle home.