Go inside to really appreciate this 500-year-old technological masterpiece.

An underground network of massive stone arches and their skylit vaults support ruins of portico structures above.

This crumbling medieval basilica once attracted pilgrims by the thousands to collect a miraculous dust that formed above the saint's tomb.

These ruins once flourished as the capital of the Lydian kingdom, often credited with the invention of metal coinage.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

A charming beach town in Turkey captures all the colors of the rainbow.

Step back in time and witness the fall of Constantinople.

1513 Turkish world map, full of European state secrets and snarky commentary.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Roman ruins top white travertine terraces formed by ancient hot springs.

This amazingly preserved Doric temple was abandoned before it was ever completed.

The world's most active stratovolcano is almost always erupting.

An image of the legendary saint stands in the shadow of a cathedral she liberated.

The largest crypt ever constructed in France was built in the 11th century on an ancient Druid sacred site.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

A favorite with sightseers and locals alike, this Norwegian funicular provides easy access to a stunning view of Bergen and its environs.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Old Danish castle immortalized in Shakespeare's Hamlet.

Climb to the top of its spiral spire for spectacular views of Copenhagen.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.