A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

A lake with hundreds of ancient skeletons surrounding it. The surprise is what killed them.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

The beauty of urban decay, hiding some dark secrets.

The most powerful waterfall in all of Europe.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

Roman ruins top white travertine terraces formed by ancient hot springs.

Legends surround this jagged rock formation in the New Mexico desert.

A small flooded ghost town with a few scattered structures remaining.

An ancient Viking village in North America that predates Columbus by 500 years.

This attraction was abandoned after the Chernobyl disaster.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

The oldest surviving synagogue in New York City is now a soaring art space.

A once grand hotel is being retaken by the wilderness it once capitalized on.

This massive redwood tree has a hole in the base big enough to drive through.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

European castle ruins in an American state park are actually the product of death and grief.

An antiquated German apothecary on Chicago's North Side.

Historic psychiatric asylum and most-filmed location in the Great White North.