The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

A band of aerialists and circus performers putting on incredible shows in East Williamsburg.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

One of New York's best collections of pinball is hidden in a secret bar in the back of this laundromat.

Try not to get slimed in Tribeca.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

A crumbling hospital from the 1850s on Roosevelt Island.

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

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

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

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

Abandoned railway line circling the city of Paris.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Legend says that this short Canadian tunnel still holds the dying screams of a girl who burned alive.

A colorful "forest" made entirely from three tons of recycled plastic waste.

A gigantic, symbolic artwork covers the side of the building.

Diego Rivera hid various people and symbols in his first large-scale mural project.

Diego Rivera's massive tiled fountain and failed infrastructure project.

A disquieting Aztec sculpture displays hundreds of stone skulls representing the victims of human sacrifice.

Visiting this cacophonous collection of vintage novelties is like stepping into the mind of a crazed toymaker.

Twelve natural mummies are displayed in the crypt of this former monastery school.

A church dedicated to the Mexican skeleton saint.

The famous artist couple lived and worked here, in two different houses separated by a bridge.