A former imperial sea-fortress and Soviet prison.

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

A decommissioned submarine base makes a great space for graffiti art.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

This serene, turquoise lake in an extraordinary nature reserve showcases a rare natural phenomenon.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

This mysterious ancient arch is hidden in the forest of Simbruini Mountains Regional Park.

A massive bridge forms part of an aqueduct that was deemed an architectural wonder of its time.

This medieval settlement was abandoned after a series of landslides. What remained was largely destroyed during a mock battle for a WWII film reel.

What looks like a link in Gondor's early warning system is actually a centuries-old Italian fortress.

This small but lovely sinkhole lake is the last remnant of a great prehistoric water basin.

A fossil of a 30 million-year-old fish is unexpectedly hidden thousands of feet above sea level.

The tallest statue in Italy is also one of the world's tallest statues of Jesus.

Just saying the name of this town out loud is said to bring bad luck.

A medieval fountain lined with 99 unique stone faces whose origins and meaning remain unknown.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

The remains of 50,000 World War I soldiers rest under a towering arch overlooking the Alpine battlefields.

This artistic temple brings together multiple architecture styles, but is only an example of one.

The 1940s structure houses what was once Europe's largest telescope.

This military mausoleum captures the solemn grandeur that most memorials only aspire to.

A visionary Italian architect created an impressive cluster of concrete structures for a family's private tomb.

This incredible second-century sculpture depicts a trio of gods worshipped by the ancient Romans.

A mushroom-shaped outcropping that has come to be the symbol for an entire town.

San Gennaro, the patron saint of Naples, greets pedestrians between these narrow city streets.