The site of William McKinley's tragic assassination is only marked by an underwhelming boulder.

This unique crypt designed by Frank Lloyd Wright for his longtime friend was not completed in either man's lifetime.

An artist's cute bronze subway sculptures belie his violent artistic past.

Infamous marsh filled with toxic waste, World War II-era London rubble, and dead mobsters galore.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

Vacant Beaux-Arts buildings that serve as reminders of a beach town’s glory days.

An underground city of salt.

A church of bones, decorated with 40,000 human skeletons.

A 168-foot tower, part of the abandoned Chester Leadworks facility.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

This little-known collection holds everything from "Dracula" notes, to the manuscript of "Ulysses," to the forged works of Shakespeare.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

A 18th century graveyard and its astonishing cortege of macabre iconography.

The final resting place of soldiers' loyal canine companions.

Protecting the dead from opportunistic body snatchers.

The tomb of one of Scotland's bloody historic villains is a magnet for bumbling desecrators.

The most loyal of little dogs, or a Victorian era publicity stunt?

The fountain marks the area where hundreds of accused witches were burned at the stake.

Remnants of the 16th-century defensive wall still stand unassumingly within Edinburgh.

A sweet symbol marks the place where torturous executions were once carried out.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.