A museum of alchemy and a basement laboratory all housed in an ancient building in a Gothic tower.

Garden dedicated to native carnivorous plants and site of huge flytrap heist.

From failed port town to Civil War fort, the ruins of this former defense saw their finest day in the television age.

A computer bug so primitive it was an actual insect.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Home to items never before seen by the public.

The United States Capitol's former columns still stand.

This tribute to the 16th-century composer is now an unusual shrine to Michael Jackson.

This beautiful 19th-century temple stands atop the ruins of its predecessor.

A fearsome dragon clings to a corner of Munich's city hall.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

A subterranean shelter remains intact under a busy Paris railway station.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

This massive library holds what was once the largest book collection in the world.

The oldest stone house in Paris was built by its most famous alchemist.

France's most famous cemetery, with some of its most curious tombs.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.