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

This home is decked out like a psychedelic explosion of colors and bowling balls.

St Bernard de Clairvaux Episcopal Church, better known as one of the oldest European buildings in the Western Hemisphere.

An underwater city for the dead.

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

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

Where manatees are the snowbird vacationers in these balmy Florida springs.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

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

A wrecked ship dating back to the American Revolution was only recently discovered off the Delaware coast.

Decommissioned NYC subway cars are dumped into the ocean to create this underwater wildlife habitat.

The longest covered bridge in Delaware.

World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

This factory made "health corsets" that were a step towards liberating women's bodies.

This strangely amalgamated museum explores the history of the Timex clock company as well as archaeology.

An abandoned 146-acre summer resort slowly being reclaimed by nature.

An overgrown and abandoned tuberculosis ward resides in the midst of a quaint modern neighborhood.

An abandoned Victorian-era mill in the middle of modern Manchester.

This enormous abandoned factory is now a makeshift graffiti gallery.

Forgotten under the construction of a new urban roadway is a small, abandoned part of town.

A few stone foundations and an old graveyard are all that is left of this once thriving settlement in the wilds of Connecticut.

Underground tunnels remain beneath this abandoned mental asylum.