This little-known relic crypt holds stolen parts of a Roman Empress.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

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

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

The first green space constructed on an elevated viaduct.

This Parisian café sticks almost exclusively to an ethos of reuse.

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

The history of radiation is on safe display at the foot of a radiation science laboratory.

This museum houses an imposing skeleton army comprised of creatures great and small.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

France's national museum of scientific and industrial instruments.

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

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

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

Abandoned railway line circling the city of Paris.

Numberless clock creates a meal of time for the dreaded, insectile Chronophage.

A treasure trove of astronomical, mathematical, and scientific instruments at Cambridge University.

The names Lúthien and Beren can be found inscribed on the shared grave of the famous writer and his beloved wife and muse.

A well for a well, this anachronistically Indian-styled water pit was built in its small town home in gratitude for a similar favor.

An extraordinary collection of scientific instruments - and Einstein's chalkboard - inside the world's oldest purpose built museum building.

An Oxford museum where visitors can have tea with the Mad Hatter and climb through the wardrobe to a fantasy land.

The Bristol Camera Obscura housed in an ancient windmill.

A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

A library where thousands of books explain how to avoid another Great Recession.