The natural mummy of the less than chivalrous Knight Kahlbutz.

Solar observatory doubles as a daring display of Expressionist architecture, much to Einstein's chagrin.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Tiny memorials honor individual victims of the Holocaust.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

The non-native bovine herd was brought in to help conserve these Berlin wetlands.

The "Prussian Versailles" that is as glorious today as when it was built.

A quaint Russian village in the middle of a German metropolis.

This Berlin island is home to a flock of free-roaming peacocks, as well as a historic ivory folly.

This concrete residential area doubles as an open-air gallery.

A 12th-century fortress containing some of Berlin's oldest buildings.

A wunderkammer of mysterious objects and stories.

This architectural oddity is an oasis of green on the outskirts of Valencia.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

This whimsical winery by Antoni Gaudí looks ripped from the pages of a fairytale.

Abandoned waterpark turned counter-culture mecca.

Living towers made of people that are now recognized by UNESCO.

Stunning Roman aqueduct used for 1900 years and still standing.

This house's itty bitty size means no humans allowed.

A 16th-century Andalusian palace.

These traffic lights celebrate the 100 year anniversary of the women's suffrage movement in Lithuania.