The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

An ancient underground cultic temple where sunlight penetrates on the summer solstice.

The ancient necropolis houses the immense rock-cut tombs of four Persian kings.

The embalmed remains of the communist leader lie within a custom crystal coffin.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

Crumbling pyramids and temple ruins stand within the shadow of this sacred butte.

Known as the leaning temple, the sacred structure has somehow developed a severe nine-degree slant.

Long tunnels run under the ancient chariot racing circuit to the tower.

No one knows the meaning behind this giant sculpture of a nude woman with a fork riding a rooster in Havana.

A dreamy mausoleum honors Persia's most famous poet.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

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

Made famous by 'Star Wars,' these troglodyte homes face an uncertain future.

Legend says if you stick your thumb in the hole and it gets wet, your wish will be granted.

This opulent 16th-century Maharaja’s palace is a unique mix of Hindu and Muslim designs.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

One of the most well-preserved temples of ancient Egypt.

Located near Cairo's El Korba district, the abandoned mansion continues to inspire mystery and rumor throughout the city.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

These strikingly colorful paintings were created by a mysterious Mesoamerican civilization.

A patchwork of ruins from various civilizations in one of the world's oldest continually inhabited cities.

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.