This irregularly shaped sea fortress has defended not one but three different sovereign states.

The house that took a plunge into the facade of a museum.

A silly medieval mural preserved on the side of a Viennese house.

An exquisite Baroque church in Vienna's old town.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

The statue of a legendary giant who carried Christ and shouldered the world's sins.

A former Latvian headquarters of the brutal KGB secret police is now open as a grim reminder of their atrocities.

Medical museum that houses most notably the taxidermied remains of Vladimir Demikhov's famous two-headed dog experiment.

Flamboyant architecture from the turn of 20th century.

3,000 market stands in five former Zeppelin hangars.

A black cat protests the City Guild in Riga's Old Town.

The oldest housing complex in Riga is a mini timeline of architectural trends.

Latvia's symbolic mountain-shaped national library is home to millions of cultural tomes.

This enigmatic artifact remained buried in a churchyard for years.

A preserved oak tree about 3,500 years old found in Riga, Latvia.

A stone marker and sculpture in the city of Riga stake a claim for the very first community Christmas tree.

Once the fallout shelter of a dictator, this sprawling bunker is now a combined history museum and contemporary art gallery.

Ancient Greek oracle of the dead.

Monasteries on rock pillars, once accessible only by frayed ropes.

This field of half-buried stone crosses was the burial place of a sect of heretical gnostics.

This open air archeological site houses almost as much wildlife as it does classical religious artifacts.

A little-known park with unusual, half-ruined structures and a mystical energy.

An abandoned Byzantine fortress and notorious prison.