A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

The place where World War I began.

Op-art architecture designed for happiness.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Over time, this castle grew to encompass the entire island.

The reconstruction of this prominent building fulfilled a long-written command.

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.

3,000 market stands in five former Zeppelin hangars.

The Guardian of Tallinn.

This soviet pilot's graveyard is filled with headstones made of airplane fins.

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

This floating sculpture of ice is a poignant reminder of nature's power.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Overlooking the burial ground is a tower designed to prevent thieves from snatching the recently deceased.

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

The most loyal of little dogs, or a Victorian era publicity stunt?

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

A scattered trail of street art adds a pop of color to the city's stark structures.

The heads of two giant mythological water horses honor Scotland's horselord past.

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.