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

A walk through the historic city center, under the streets of Seattle.

A one-of-a-kind collection of a unique medium.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A layered tribute to the work of mosaicist Isaiah Zagar.

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

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

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

New York's oldest magic store.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

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

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

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

Dramatic river bend surrounds a natural red-rocked pedestal.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A 140-year-old castle with underground caves hidden in San Francisco.

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

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

On the Oregon coast there is a natural hole that seems to be draining the sea.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

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