Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A tiny church on a man-made island in the Adriatic.

Gargoyle head that brings good luck.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

An ancient knight and a symbol of the city's freedom.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

The walls and streets of the ancient city are peppered with penises.

Erotic art covers the walls of the largest ancient pleasure palace.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

Italian cave with exceptional acoustics and an unsavory history.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

Peeing dogs guard the Roman hunting goddess atop a fountain at France’s Château de Fontainebleau.

This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

Inspiring Herman Melville and Henry David Thoreau, Mount Greylock in western Massachusetts is the highest point in the state at 3,491 feet above sea level.

Solar powered Spectacle Island features all-green facilities.

Overgrown ruins of a turn of the century island fort that sees very few visitors.

A disastrous shipwreck and a tragic love story.

Hut with supplies for shipwreck survivors.

Civil War-era Fort designed to withstand invasion and attack, with tricky traps called "murder holes."

Civil War Fort on an island in the Boston Harbor.

Last church of this militaristic WWII style.