An unusual round church in London with a Templar past.

Ancient cliffs resembling a kilt on Scotland's second largest island emit an entrancing sound.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

An underground city of salt.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

Real bones which are said to have belonged to a Polish dragon.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

A statue honors the children who fought Nazis in Poland.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

A popular rock that acted as a waymarker for American pioneers.

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

A display of magnificent stained glass windows is the first exhibit of its kind.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

A priceless collection of the Nation's cryptologic history.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

A field in which God and his son Jesus purportedly appeared to a young farm boy named Joseph Smith.

This Niagara Falls tourist trap is a world bright with neon and curiosities that will inspire love, hate, or a mixture of both.