Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

The land is home to swimming ponies and a legendary 18th-century treasure.

Bizarre Cavern.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

The plague quarantine island home to the alleged "Vampire of Venice."

Venice's "Island of the Mad."

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

A collection of objects supposedly singed by the hands of souls in purgatory.

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

The underground sanctuary of a mysterious ancient cult.

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

2300-year-old Roman road connecting the empire.

The final resting place of the poets Shelley and Keats.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

An alchemist's "magic door" stands in the middle of a Roman park.

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

Architectureal fantasy quarter of Rome.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

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