WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

This ancient Visigothic church might hide an ancient treasure.

Once the grandest synagogue in medieval Spain, it now stands as a memorial of the 15th-century Jewish exile.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

A lush indoor jungle fills this bustling Madrid transportation hub.

A controversial memorial at the place where Captain Cook met his violent end.

This black shoreline is made up of exploded lava particles.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

Looking strangely like Rome's Colosseum, this unfinished tower has dominated the skyline for over 100 years.

A small island abbey is the final resting place of many medieval Scottish monarchs, including the real Macbeth.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

A fantastic reconstruction of a 10th-century Viking longhouse.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

A trio of hidden hot tubs takes advantage of Iceland's natural geothermal vents.

Staves, storm-calling, and of course, necropants.

This sensational Chinese temple walks visitors through the 76 weird departments of the afterlife.

This historic Chinese tower was said to have been haunted by fox spirits but is now haunted by a grisly murder.

Ming Dynasty necropolis raided during the Cultural Revolution.

The most famous location in China was home to whole dynasties worth of imperial rulers.

The beautiful baroque library of the Hapsburg empire.

This stunning and ethereal mural symbolizes the beauty, unity, and diversity of humankind.

The most complete statue of this Aztec god sits a top a throne carved with images of hallucinogenic plants.

This ancient jade mask depicting the Zapotec bat god was found in the ruins of the pyramids of Monte Alban.