The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Try not to get slimed in Tribeca.

Home to an endangered salamander, a full moon celebration, and a large spring-fed outdoor swimming pool.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

This distinctive Crescent City tradition dates back to the days of horse-drawn carriages.

By day this New Orleans square is for pedestrians, but by night it is a kingdom of kittens.

A museum and shop on Bourbon Street located in the French Quarter.

The oldest cemetery in New Orleans, resting peacefully for over 200 years now.

At 135 years old and counting, this historic print shop is heaven for poster nerds and music buffs.

This replica of the Greek structure is in the heart of Nashville.

The glowing blue Nymphaeum of Emperor Tiberius.

Ancient ruins hidden underneath a modern luxury hotel.

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

2300-year-old Roman road connecting the empire.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

An ancient octagonal weather station named for the eight Greek gods of wind.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Replicas of Apollo's leonine stone guard cats still line a sacred row in Greece.

Giant marble phalluses on the sacred island of antiquity.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

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

Stunning Roman aqueduct used for 1900 years and still standing.