This family-owned diner has been slinging chili dogs since 1940.

Used as a military post in three different engagements, this fort has remained incomplete and unfired upon for nearly 200 years.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Deep in the countryside lie the remains of one of the grandest Roman dwellings in Britain.

The ruins of a once-thriving sugarcane plantation that was burned in the Second Seminole War.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

A luxurious 1880s hotel with its fair share of Tiffany stained glass, Edison electricity, and of course, ghosts.

One of the oldest, tallest, and most haunted lighthouses in America.

These unusual rooms on wheels are holdovers from the 1960s.

An important landmark in the history of algebraic logic.

This 19th-century prison once held Irish revolutionary Constance Markievicz, writer Frank O’Connor, and a nine-year-old pickpocket.

Aside from denoting a public square or market, this medieval structure was also a sign of a town's prosperity.

This permanent collection of preserved bodies taken from Irish bogs is one of the leading authorities on such morbid mummies.

The mummified heart of a saint lives on in this church—after a brief hiatus when it was stolen.

An impressive Neolithic henge with banks nearly 10 feet high.

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

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

Though this large circular site is now named for the legendary king, its history dates back to the Neolithic era.

The Stonehenge of Wales is one of the grandest neolithic dolmens still in existence.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.