A crumbling hospital from the 1850s on Roosevelt Island.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

A terrific purveyor of natural history objects and curios.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

France's Lilliputian park displays over 100 of the country's monuments for visitor perusal.

One of Jeff Koons’s largest sculptures and his first commemorative work.

What looks like a normal building is really a hollow facade hiding a subway vent.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

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

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

The narrowest street in Paris.

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

The curious underground history of keeping Paris clean.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

The first green space constructed on an elevated viaduct.

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

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

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

A surrealist timepiece by the artist of melting clocks.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

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.

The very center of Paris is surrounded by a bevy of strange good luck rituals.