An ancient Egyptian temple in the middle of Madrid, Spain.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

A controversial art piece that harkens back to local folklore.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

Paris' linguistic guide to the international language of, yes, love.

Little Red Lighthouse under the George Washington Bridge.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

The first and only carousel with a lineup entirely of insects.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

A very classy 1920s-era bar right in Grand Central Station.

The "Seinfeld" diner.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A semi-scholarly approach to sex.

Elevated freight railway turned wildly successful urban park.

This house's itty bitty size means no humans allowed.