An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

One of Mexico's least-visited archaeological sites is tucked away inside a theme park.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

This 15-foot former Johnny Appleseed has given up his apples for donuts and coffee.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

A small but very fascinating fountain in the center of Rome with four books and a deer carved.

According to local folklore, this Roman sepulcher was once a throne for the Devil.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

Its interior is adorned with some of the best examples of early Christian mosaics.

This is the oldest Roman-made bridge in the city still existing in its original state.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

2300-year-old Roman road connecting the empire.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The yawning maw of this pagan visage is said to bite off the hands of liars.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This wildlife refuge is home to more than 200 species of birds, as well as monkeys, lizards, and other wildlife.

In Costa Rica's cloud forest, the roots of a woody ficus create a botanical bridge.

These mysterious ancient stone spheres were created by a civilization lost to time and are now mostly lawn ornaments.