Sweden's largest optical telescope sits on a rooftop in Stockholm.

Once the world's biggest telescope, it was later used as a coat hanger by a famous Dutch astronomer.

The largest refracting telescope in Europe is housed on the grounds of a former French castle.

Learn about stars, weather patterns, or just enjoy the panoramic view of Ghent.

The world's largest single-aperture telescope resides in the Canary Islands.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.

One of the largest refracting telescopes in the world, and the first built specifically for studying astrophysics.

Possibly the world's only drive-in movie theater with an attached motel.

Sleep beneath the big screen at this old-school movie theater.

Featuring the largest CinemaScope screen in Pennsylvania, this drive-in has entertained moviegoers for more than half a century.

Opened in 1947, this is the oldest continuously-operating drive-in theater in New York.

Georgia’s last drive-in movie theater is a relic of a bygone era.

America's oldest drive-in movie theater has been in continuous operation since 1934.

Though nicknamed the “Russian Freighter,” this ship was actually sunk off the coast of Pensacola by the U.S. government in a top-secret operation.

The 44,000-ton aircraft carrier was purposely sunk to create an artificial reef teeming with life.

An idyllic swimming pool tells the tale of Hemingway's trouble with women.

This 140-year-old beacon off the Florida Keys marks the wreck of a Navy ship that once roamed the Caribbean hunting pirates.

A humid oasis combines recreation with exploration in a unique underwater cavern.

This ancient sinkhole-turned-healing-pool is a treasure trove of archeological discoveries and may even be the Fountain of Youth.

The scuba diving training facility was named for the steam that rises from the cave's chimney.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

An underwater statue of Christ blesses the depths off Key Largo.

The historic villages and towns of Suffolk are filled with wonky wooden beam houses painted an unusual shade of pink. Unknown to many though, this sweet shade has a bloody history.

This secret Swiss fortress is disguised as a harmless pink house, complete with fake windows.