Edison's cast-in-place concrete houses were a failure, but way ahead of their time.

A farm in New Jersey grew a most unusual crop for AT&T's testing purposes.

An enormous overgrown greenhouse teeming with graffiti and wildlife.

A world-class collection of mechanical musical instruments and automata.

This hospital fell into ruins after failing to act as the advocate for the mentally ill it was designed to be.

A recently abandoned psych ward at the end of Sanatorium Road.

A unique sculpture park that specializes in the huge and bizarre.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Sometimes called the Banksy of Madrid, Muelle was a pioneer of street art in the Spanish city.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Traveling this mountain pass reveals quaint stone buildings, stunning Irish scenery, and a bridge said to grant wishes.

An 1814 castle that hosts an exhibit of "explorabilia".

A spectacular hidden beach in Ireland has the dark, disturbing nickname of "Murder Hole Beach."

The oldest public library in Ireland.

The world of the ancient Celtic civilization explained through a bewitching 11 acre garden.

One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

An eccentric garden of sculptures crafted in India decorate an Irish green space dedicated to Alan Turing.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

When this 18th-century observatory's meridian was moved, it set Sweden's time back by 0.04 seconds.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

The remains of Alfred Nobel's first nitroglycerine factory can still be found on the shores of a Swedish bay.