This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

One part local history, 99 parts gruesome haunted house.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

Massive galleon from a box-office bomb docked in Genoa.

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

Ancient snack bar of the Roman Empire re-opened.

100 year tradition of fist fights, marked by marble footsteps.

Venice's island of the dead.

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

A historic Montreal market that was the city's agricultural hub for over century.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Louise Bourgeois' 30-foot-tall steel spider sculpture.

Canada's largest graveyard boasts a lot of noteworthy artifacts as well as its own computerized mapping service.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

A massive Montreal stadium that has seen nothing but trouble since its inception.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Hundreds of hidden passageways weave through the old quarters of Lyon.