This unique rock formation is quite the local celebrity, although one day it may come crashing down.

This local emblem is the oldest and largest dragon tree in the Canary Islands.

A shopping mall housed in a historic cinema and hiding ancient ruins under its floors.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

A gigantic statue of a Russian soldier watches over the ancient city of Plovdiv, a prominent reminder of the Soviet period in Bulgaria.

Commonly acknowledged as the only public monument to the Devil himself.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This once-derelict building is now one of the most beautiful bookstores in the world.

Check out engineering marvels of the past at this unintentionally retrofuturist museum.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

A huge communist-era propaganda monument and mural that offers stunning views of the Mongolian capital.

The world's most elegant power lines.

This centuries-old tower hosts endangered bald ibis mating pairs and looms over a pristine beach.

Italian cave with exceptional acoustics and an unsavory history.

A sharp sculpture made of thousands of pieces of jagged glass.

An ancient Egyptian temple in the middle of Madrid, Spain.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

The little church's beautifully frescoed ceiling has earned it the nickname “the Sistine Chapel of Madrid.”

A lush indoor jungle fills this bustling Madrid transportation hub.

A haven for book enthusiasts across the street from Retiro Park.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

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

Meant to resemble a massive tree, the building is the best example of Spanish organicist architecture in Madrid.