This piece of early engineering is rather unknown despite its location in the heart of Madrid.

2300-year-old Roman road connecting the empire.

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

For 20 years, local pumpkins have met their fate on the iron fence surrounding this Cobble Hill home.

This pump on the bad side of Victorian London betrayed a horrifying revelation about the water supply.

This pub has roots dating back to 1430.

The final resting place to 300 Victorian-era pets hides inside the city park.

This black cat was actually designed to ward off bad luck.

A kaleidoscopic warehouse-maze of handmade neon signs.

An arsenic-filled pool in the Grand Canyon takes on the appearance of a giant, overflowing pumpkin.

This inn of the court provides a fascinating window into London’s legal and architectural history.

A cluttered and astounding collection of antiquities and curiosities.

The anatomical-pathological collection of a man who changed surgery.

London's old-school healing garden.

On one of the world's most active volcanoes, a pebble-filled crater changes color with the wind.

After giving up Michelin glamour for his Amish faith, one chef now makes stellar sausages in a small, off-the-grid shop.

This hauntingly beautiful cemetery outside a medieval citadel is full of winding paths and ivy-covered graves.

Site of a famous 19th-century transcendentalist utopian community, now abandoned.

Three prestigious academic collections come together to create a world-class natural history museum.

The oldest Italian café in Boston, this spot also serves as a veritable museum of vintage coffee ephemera.

Enjoy an overnight at an old haunted B&B site of the Borden family murders.

Of all the unique artifacts inside this library, a mummified hand stands out among the others.

Not to be confused with the iconic New York City skyscraper, this Chicago building is a vibrant hub for artists.

A strange and haunting monument of unknown origin in the historic Graceland Cemetery.