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

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

A submerged archeological park still holds the wonders of a Roman Sodom.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

A massive underwater sinkhole made famous by Jacques Cousteau.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A huge musical instrument played by the ocean.

A high point in Vancouver kitsch.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

This Art Deco masterpiece has stood in for some of the most famous buildings in comic book history.

This massive, ancient stone was disassembled and then put back together again.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

A well-preserved network of cavernous tunnels have spent silent centuries removing Toronto's waste.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

A Nesting Doll of Churches.

2300-year-old Roman road connecting the empire.

The underground sanctuary of a mysterious ancient cult.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The studio built by fascists in the hopes of "reviving the film industry" with the occasional propaganda film opportunity thrown in.

This Austrian museum celebrates the work of famous forgers and their inimitable imitations.

This giant expressionist head crowns a museum devoted to a beloved Mexican leader.

Meant to be one of the most extravagant hotels in the world, now an eerie, abandoned architectural gem in Mexico City.