The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

A giant replica of an Assyrian cuneiform tablet stands in the middle of a busy intersection near the city center of Kayseri.

Mausoleum and Holy Seat of Antiochus I of Commagene.

This arch granting triumphal entrance into Antalya was designed to honor the emperor's visit.

3,000 market stands in five former Zeppelin hangars.

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

This charming Latvian lane doubled as Baker Street on the Soviet Union’s version of Sherlock Holmes.

A striking Soviet memorial commemorates the liberation of Belarus from the Nazis.

Glowing orb in Minsk houses 8,600,000 items.

A sculpture of graceful storks sits atop this fountain in Independence Square.

Remnants of the city's Soviet history hover over this modern fast-food outlet.

Dedicated to the lives lost during a fatal stampede in the Nyamiha Station.

This Minsk museum has cat coffee, cat chess, cat art, and even a cat "staff," which visitors are free to take home.

The secret meeting held in this building would forever change the world.

The apartment building where JFK's assassin lived after defecting to the Soviet Union.

A beautiful and moving memorial set on a little island in the middle of the river in Minsk.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Time stands still at this serene burial ground in the center of Budapest.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

From cartoon characters to tiny tanks, a guerilla sculptor's little bronze statues are hidden throughout the city of Budapest.

Valletta’s outdoor theatre stands within the ruins of a 19th-century opera house.

Get in line for Lisbon’s most famous sandwich.

An unassuming music museum recounts the rags to riches story of a dramatic Portuguese genre.