The prototype for all Nazi concentration camps.

This splendid tomb may look fantastic, but there's nothing in it...

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

A New Zealand communications tower stands as the tallest structure in the Southern Hemisphere.

The real life Hobbiton, this sheep farm has been forever transformed since being built for The Hobbit film series.

Tubing through a cave lit with glowworms is a magical underground experience.

The shallow, salty inlet was a safe haven for 19th-century pirates.

A tiny Greek Orthodox church from the Ottoman era hides on a busy city street.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

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

The ruined doorway is a portal to the building's turbulent and torturous past.

An ancient octagonal weather station named for the eight Greek gods of wind.

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

An ancient Greek monument and a Byzantine church coexist inside this cave.

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

The only surviving choragic monument is a trophy awarded in 334 BC for the winning dramatic chorus.

One of the greatest collections of coins in the world is housed in the former mansion of an archeological pioneer.

This striking sculpture of Icarus honors Greece's fallen flyers.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

You can walk through the first Boeing Air Force One, which famously carried JFK's casket from Dallas back to D.C.

Inside houses a vast collection of military aircraft and missiles spanning the ages.

Inside this wonderland of weird, visitors are treated to a collection ranging from skeletons to haunted artifacts.

This recently restored timepiece has stood all around Kansas City.