The site of the climactic scene from the classic horror film is now a historic landmark.

A Nesting Doll of Churches.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

Ancient ruins hidden underneath a modern luxury hotel.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

Architectural monsters are devouring this palace's every door and window.

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

An unfortunate geological resemblance to Satan has labeled this Pasadena gorge as a passage to the underworld.

NASA's leading space science lab started by a co-founder with deep ties to the occult.

The collection of intricate sculptures includes one carved from a mammoth's tusk

Discarded animal sculptures stand forgotten by an abandoned aquarium and water park in Bosque de Chapultepec.

A "time traveler's" vision of human history stretches throughout Mexico City's Copilco metro station.

These subterranean models show Mexico City's central square during three different eras.

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

This museum houses two of Mexico's most impressive Aztec monoliths.

Come face to face with the ferocious visage of the serpent-headed mother goddess of the Aztecs.

The turquoise-studded skull of a long-dead Aztec man sits within Mexico City’s Museum of Anthropology.

Once home to an aristocratic family and a workers' organization, this intricately tiled building now houses a chain restaurant.

Inside a busy metro station, an impressive mural depicts the prehispanic city of Tenochtitlán.

Many people don't realize there’s a lot going on in—and below—the world’s tallest triumphal arch.

The most complete statue of this Aztec god sits a top a throne carved with images of hallucinogenic plants.