A semi-scholarly approach to sex.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

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.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

Radical Bookstore and Community Space.

America's original house of worship for Spiritualism, the religious movement based on communing with the dead.

Dim sum, served in a grand old theater.

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

One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

An enormous, inside-out glass globe built in 1935.

Two thousand artifacts from around the world collected by one woman who loved to travel.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

Inside the Šomoška National Nature Reserve exists a unique rock formation rarely seen in the world.

This clifftop arch is a natural stunner.

Featuring the last fully walkable parapet walkway in Europe.

A narrow opening between the mountains of the Amalfi Coast creates a scenic hidden beach.

The steel cable lets adventurers zoom between two mountain towns at speeds of up to 75 miles per hour.

The abandoned ruins of a failed resort hide on this verdant, picture-perfect island.

This seaside Italian village doesn't just look Escher-esque, it actually inspired the mind-bending artist.

A line of abandoned, alien-like fortresses dot the mountains of North Italy.

Dramatic sea stacks adorn the coast of this small village on the Adriatic coast.

This medieval Italian town is a sheer (and beautiful) cliffside defense.