Traditional 11th-century outdoor tannery.

The other side is actually green.

Mosaics, storks, and brothels—this ancient city has it all.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

This historic streetcar system has been running since the 19th-century.

Elaborate tile work in this railway station tells the story of Portugal.

Gustave Eiffel's masterpiece until the Eiffel Tower was built.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

One of Ohio's longest history books isn't made of paper—it's painted across the floodwall.

This ancient village provides insight into the complexity of the pre-Columbian Fremont Culture.

This cultural center showcases what may be the oldest ongoing community in all of North America.

This rural community has attracted both scientists and techno-refugees due to its federally-mandated lack of technology.

The 80-foot tire that looms over Michigan's I-94 was once a Ferris wheel in the New York World Fair.

Ghost stories surrounded this “castle,” the only structure from a huge mansion that was never built.

Known as "The Dome" this is the world's largest open air geodesic dome.

The longest-serving U.S. Secretary of State and Nobel Peace Prize winner was born in this humble cabin.

This steamer is known as "The ship that built Cleveland."

A throwback train ride transports passengers through one of the lesser-known national parks in the country.

A lighthouse on this West Virginia lake started as a joke, then the forces of nature helped make it a reality.

This former tuberculosis treatment facility now stands at the center of a public park.

The farm where one of America's greatest leaders was raised is now a well-appointed landmark.

Victory on this battlefield catapulted William Henry Harrison to the presidency in 1840.

This small piece of Michigan is entirely surrounded by Ohio.