The largest catacomb system in the world.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

This 19th century cyclorama acts like an analogue time machine to a different era.

A line of disused military bunkers built to defend against Nazi invasion lies hidden on the outskirts of the city.

Austria's very first and only nuclear power station was completed but never used.

A spherical "micro-nation" in the heart of Vienna.

Visiting this café is like visiting the Austrian grandma you wish you had.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

Legends surround an ancient tree trunk riddled with nails for good luck.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

Armenia's premier center of astrophysical research was established during the Soviet era.

Giant stone letters dedicated to the founder of Armenia's alphabet.

The most visited pilgrimage site in Armenia once held a saint in a pit for 13 years.

A cylinder monument with a spectacular vista commemorates a friendship that some say never existed.

Unusual building appears to be haphazardly built from randomly piled bricks.

The last standing example of an ancient district's teatime tradition.

Luxury hotel turned into a refugee camp, then turned back into a luxury hotel.

One of the most horrible legacies of the Cold War is a site where the Soviet Union tested nuclear bombs on civilians.

Nightmarish example of the unintended consequences of weapons testing.

Pictures tacked onto trees remember the more than 40,000 of Stalin's victims buried here in mass graves.

An incredibly random collection of wax figures is displayed in a shopping center walkway.

Acres of salt crystal pyramids dry in the sun along Thailand's "salt road."

An enormous dragon scales the walls of this 17-story temple.