Houses are tucked between, on, and underneath giant boulders.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

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

The beautiful, ornate weather station is the most popular geocache in Salzburg.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

Apartment complexes built into huge repurposed natural gas tanks.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

An exquisite Baroque church in Vienna's old town.

The Habsburgs' royal collections of art and wonders.

Op-art architecture designed for happiness.

Baroque celebration of the end of the Great Plague of Vienna.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The topiary maze at the Habsburg hunting lodge.

The final resting place for the remains of 143 Habsburg royalty.

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

The beautiful baroque library of the Hapsburg empire.

At this rare mosque in Tbilisi, Sunni and Shia Muslims pray side by side.

A small but hugely whimsical theater where marionettes play out the "The Battle of Stalingrad."

This architecturally eclectic fortress witnessed centuries of bloody turmoil, including the massacre of its ruling clan.

A museum glorifying the life of Stalin, located in the city of his birth.

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.