The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

A room filled with frescos that make it seem like the walls are crumbling down while giants die in despair.

This ancient amphitheater was restored in the early 1990s.

This was the second largest mercury mine in the world and one of the oldest preserved mine complexes in Europe.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

According to a local legend, this old castle could only be built after a woman was immured in the walls.

This open-air, narrow-gauge railway museum pays homage to the region's transportation history.

One of the most exquisite Lycian hilltop citadels in Turkey.

This is one of the last surviving structures of a once vast palace complex.

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

This human-made pond is part of a Korean palace complex first built in the 7th century.

This 13th-century monastery chiseled into the side of a mountain is equipped with a bridge that can be lifted to protect against raids.

This hermitage spanning an Italian river gorge draws pilgrims hoping to heal ailments like arthritis and migraines.

In a divided Germany, Potsdam's "central" train station was relocated to the city's southern suburbs to avoid West Berlin.

Now overgrown, these anti-tank barriers from World War II are sometimes called "dragon's teeth."

According to legend, those who pray at this statue will also be granted a wish.

The largest Roman amphitheater in the Balkans once held over 20,000 people, but managed to lay hidden for hundreds of years.

This statue honors one of Budapest's most beloved literary characters.

Located in the middle of public park, this cave built in the early 19th century houses an ancient stone sarcophagus.

The largest covered bazaar in the world.

This fort dates back to 1588 and was colonized by the Portuguese, Dutch, and English and sits prominently on the Indian Ocean where azure water lap the coast.

Of five volcanoes located in the massive Tengger caldera, this cone is the youngest and most active.

One of the world’s longest pedestrian suspension bridges.

Of the many Jesuit missions in South America, this complex is one of the best preserved.