Washington D.C.'s most famous pianist, composer, and bandleader still tickles the ivories outside Howard Theater.

Cold War intelligence agents monitored communist embassies from an attic in a former pigeon coop.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

Only a fragment of this 15th-century Dance of Death survives today.

The Guardian of Tallinn.

A medieval setting reimagined into a unique art alley.

During the Soviet era, the spire of this longstanding church was used as a radio transmission tower.

Disused seaplane hangar gets a second life as the jaw-dropping home of Estonia's museum of maritime history.

The last surviving submarine from a strange chapter of Finnish history.

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

This church also serves as a lighthouse complete with a beacon.

A subterranean house of worship carved right out of the bedrock.

An alien church provides much needed silence in the midst of a Finland shopping center.

Dedicated to the outnumbered Finnish forces who pushed back Soviet forces during the conflict.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.

The tiny, studious rodents greet visitors to the National Archives of Finland.

This restaurant combines two Finnish traditions in one place: warm-weather relaxation and outdoor carpet-cleaning.

These enormous, stern-faced statues greet visitors with lanterns, and sometimes costumes.

An Irish Memorial commemorating those who perished due to potato blight.

Believed to be the birthplace of the United States Marine Corps.

Mural made of 100,000 pieces of hand blown glass, and one of the largest glass murals in the US.

The video game-themed street art first popped up in the French city.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.