An overlooked memorial honoring the local Washington residents who died in World War I.

Decades before the scandal, this staircase on the river was a literal "water gate."

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

A former major munitions plant that has been converted into a sprawling art space.

The only place for a truly presidential dram.

César Baldaccini's iconic sculpture of a 40-foot thumb stands tall in La Défense.

The final resting place of the "father of special effects."

This demon atop the Notre-Dame de Paris looks utterly bored.

A museum which takes visitors to the côté obscure of Paris.

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

Noirish green neon marks the location of one of the oldest private detective agencies in France.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

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

A surrealist timepiece by the artist of melting clocks.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

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

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.