Legend says this sacred tree was a gift from goddess Athena.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

In the hometown of the Catholic saint and Nobel Peace Prize winner, a memorial dedicated to her legacy.

This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

An office built to look like a giant basket.

Oriental bazaar in the heart of Sarajevo.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

The angel of death appears to weep black tears at this grave marker.

A dazzling display of lights and crystals.

The rocks of a certain area of Butte, Montana give off a musical ring when hit.

One of the last socialist halls still standing in the United States.

The oldest continuously-operating Chinese restaurant in the United States has been in business since 1911.

A sprawling museum located on the former site of the Orphan Girl Mine.

A collection of huge, site-specific sculptures sitting in the Montana woods.

A real flying saucer, contracted by the U.S. Air Force.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

The place where World War I began.

Now in disrepair, this 19th century station was a stop on of the famed B&O Railroad.

Inside, ancient treasures. Outside, modern contradictions.

An unusual, super-sized grocery adventure awaits in an Ohio suburb.

A marvel of Byzantine engineering under the streets of Istanbul.