19th century tunnels burrowed under Liverpool.

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

Go inside to really appreciate this 500-year-old technological masterpiece.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

Breathtaking and huge 430 year old maps of Italy.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

A sculpture serving as an homage to Pope John Paul II.

Gutted during the Liverpool Blitz, this architectural husk has been left destroyed in honor of the dead.

The tower was originally used as a chimney for the waste incinerator of St. John's Precinct and Market.

A community of artists and entrepreneurs seeks a simpler life on London's waterways.

This intricately carved and hilariously huge bed was such a famous symbol both Shakespeare and Byron used it in their writing.

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

Catacombs turned marketplace.

William Faulkner kept his beloved estate wild and untamed.

The world's longest known cave system.

This open air cathedral invites all faiths to worship under the only roof big enough to fit them all: the sky.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Man-made geyser that rises to the exact height of the Gateway Arch.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

Speak to a companion on the other side of the room loud and clear through this architectural anomaly.

Less a museum than a bizarre fantasy world created by artists and engineers.