A relic of the Cold War tucked away in the forested hills above Bratislava.

Site of the 1889 murder-suicide of crown prince Rudolf and his lover Mary Vetsera.

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

Located right outside of Vienna, visitors can take in expansive views of an ethereal forest.

More than a millennium's worth of municipal records preserve the political history of Austria.

This grand manse has been transformed into a museum devoted to one of the founders of Fantastic Realism.

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

In the fictional world of Kcymaerxthaere, standing at this site just outside Vienna, Austria, the sky would have been found beneath your feet.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Apartment complexes built into huge repurposed natural gas tanks.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Op-art architecture designed for happiness.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Dine amidst exotic plants at this former royal greenhouse.

The first modernist church in Europe.

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

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

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

A gift from Emperor Franz Joseph I to his wife.

The topiary maze at the Habsburg hunting lodge.

An ornate private entrance to the Vienna subway built specifically for the emperor.

This cubist Vienna church building looks like some sort of alien stonehenge.

This failed condo development was reborn as a street art hub.

Controversially claiming the title of world's biggest bass drum, UT's Big Bertha was once made radioactive by the Manhattan Project.