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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

Dramatic river bend surrounds a natural red-rocked pedestal.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

An emerald-green grotto just a short trip from Austin.

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

Most-visited and most-photographed slot canyon in the American Southwest.

A crumbling hospital from the 1850s on Roosevelt Island.

World's first "penitentiary," meant to be humane, drove men insane.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

Rippling sand dunes frozen in the Arizona rock.

A well-preserved network of cavernous tunnels have spent silent centuries removing Toronto's waste.

The Victorian-era greenhouse is stuffed with tropical plants, and open 365 days a year.

With the chapel itself being left to moulder, the cemetery of this abandoned church might be the freshest part.

A spoke-tacular artwork constructed from recycled bicycle rims.

This notorious Canadian mental institution was home to some of the first LSD experiments and origin of the word "psychedelic."

Outsider art meets hard scrabble mountain life in this woodcarver's home/art piece.

This little Vancouver shack is a temple to all things Hendrix.

Secret Swing.

These prehistoric replicas were based on actual skeletal remains.

This mid-19th century chapel is a tiny treasure for weary travelers.