On a clear day, you can see all the way to the Virgin Islands from the top of this observation tower built in the 1960s.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This small primate research island is teeming with playing, fighting wild monkeys.

This former sugarcane transport tunnel is now a portal to a lovely beach.

Elephant seals and sea lions have turned the abandoned buildings on this island into their endangered love shack.

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

This airfield is home to a number of retired vintage planes in various states of disrepair.

The abandoned bathhouse is all that remains of the hot springs considered Florida's original tourist attraction.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.

This jail once controlled by the Japanese military now sits abandoned on a remote Pacific island.

An abandoned network of military bunkers and tunnels open for anyone willing to descend into the darkness.

A forgotten Cold War relic hidden in the outskirts of a Wisconsin city.

Ruins of a historic medical facility sits eerily by the water.

The NBA player's elaborate former home is now a ghost of its old glory.

A mining town, now abandoned, was built in a canyon so narrow that the railroad ran right through the hotel lobby.

The crumbling structure is a rare surviving relic of the area's bygone mining industry.

A Christian-themed amusement park and complex rocked by scandals.

The location of Puerto Rico's first water bottling plant, thanks to a collaboration between Mother Nature and technology.

This 45-story tall abandoned skyscraper is the third tallest building in New Orleans and Lousiana.

This now-abandoned outcrop is an important Native American spiritual site, overtaken by European settlers and mining pollution.

Inside a state forest, the forgotten remains of a Cold War defensive installation.

Accessible only by boat, this centuries-old island fort never saw troops or combat.

Once luxurious, these oceanfront beach homes have been left to succumb to the elements as the beach is slowly washed away.

Take a self-guided tour through one of Colorado's most elevated mining districts.