This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

The oldest arched-covered bridge in Virginia has truly withstood the test of time.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

A genuine Tudor manor transported piece by piece from England.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

This historic mansion was built as a symbol of love between a husband and wife.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

Giant busts of 42 U.S. presidents are sitting in a field in Virginia.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

What began as an art installation is now the private drinkhaüs for a brewery's employees.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Hideout of thieves, monks, and goat-footed gods.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

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

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

Monasteries on rock pillars, once accessible only by frayed ropes.

The hallucinogenic center of the ancient world.

A spectacular cave and a beguiling lake.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

These murals stand as reminders to the troubled history of this Northern Ireland city.