Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

Mysterious rocks that ring musically when struck.

A rare view of a preserved Victorian science museum.

An abandoned castle owned and ignored by Masons carries a cursed history.

This Parisian gem is one of the most incredible ethnographic museums in the world.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

The narrowest street in Paris.

This banal Parisian entranceway is not what it seems.

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

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

A modern-day Lascaux cave underneath Paris.

The curious underground history of keeping Paris clean.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

An off-the-beaten-path boutique stuffed with an eclectic collection of upcycled goods.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

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

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

This Parisian fountain is a little bit fantasy and a little bit nightclub.