This Florida sinkhole hides a rainforest-like micro-environment in its depths.

The birthplace of American international flight service has been turned into a celebrity's microbrewery.

Florida's oldest bar was once a morgue, complete with a hanging tree and gravestones.

The museum chronicling a treasure hunter's dream, fulfilled.

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

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

A monument celebrating the idea of reaching inaccessible places.

"We Seceded Where Others Failed."

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

The famous boat that once ferried Bogart and Hepburn still floats in Key Largo after being abandoned for years.

A mysterious castle built as a monument to lost love.

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

An icon among Florida's pre-Disney tourist attractions.

A vast array of tropical plants collected by a vacationing couple.

This abandoned NASA launch site is now a memorial to a trio of astronauts who were killed there.

A building so large that it has its own weather.

A swamp that was the site of prehistoric water burials also managed to preserve its corpses for millennia.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.