A massive underwater sinkhole made famous by Jacques Cousteau.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

Three buildings constructed of over 25,000 multicolored glass bottles.

The final resting place of New Orleans' most famous voodoo priestess.

This abandoned Civil War fortress is slowly being swallowed by the waters of Lake Borgne.

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

The crumbling remains of a 19th century fortess.

Once defending the city of New Orleans from invasion by sea, this fort faces an uncertain future.

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

Off of the Crawfordville Highway in Florida, nature is taking back this decrepit row of Ford trucks.

A giant 400-acre preserve in North Florida for displaced wolves.

The remains of an idyllic small town built for the film 'Big Fish' still stand around a rundown main street.

An unfinished rail tunnel that has since been used to house cheese and bats.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

Mysterious ancient boulder carved with petroglyphs in the mountains of Western North Carolina.