The remains of Crystal Palace Great Exhibition of 1851.

Remnants of a Victorian garden feature sitting in public woodland.

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

A clock designed to run with perfect accuracy for 10,000 years.

Traveling collection of amazing automata.

Hidden beneath the streets of London is a secret subway that only carried mail.

Eighteen mummies have stood guard behind the altar of this tiny church since 1833.

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

These delicate sand pyramids look like naturally occurring gothic spires.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

The world's oldest surviving anatomical theater, where "the dead are pleased to help the living."

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

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.

Former utopian colony based on the belief that the universe exists in a hollow sphere.

An abandoned vacation home spent a decade taking on legends. It's now taking on water.

Prehistoric animals decorate this popular outdoor park.

A museum to a cave explorer whose tragic death was a media sensation, and whose corpse became a tourist attraction.

This landmark of the Chicago silent film industry may not be in the picture business anymore but it still stands proudly.