This limestone cave offers an incredible view of the Río Grande de Arecibo valley.

The world's brightest bioluminescent bay.

Legend has it this historic port was a popular hideout and smuggling spot for pirates.

A magnificent waterfall nestled in the heart of the El Yunque National Forest.

An enchanting natural wonder in Puerto Rico's Camuy River Park.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

On a small Puerto Rican island, banks of secret naval bunkers lie abandoned and filled with piles of office equipment.

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

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

This niche museum devoted to ancient religious artifacts is shaped like the very thing it displays.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

This chapel on a cliff is renowned for its healing powers and was founded on the site of a supposed divine intervention.

The world's second largest single-dish radio telescope, once used to contact E.T.

Beneath the surface, something slithers. And if you find it, prepare to be slimed and glowing.

More than five miles of underground passageways.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

A bizarre roadside attraction and the first instance of miniature golf in the world.

A mysterious monument meant to be a guide into "an Age of Reason" was destroyed after an apparent bombing.

A mural in rural Georgia welcomes visitors to a fictional Missouri town.

A vision of beautiful Hindu architecture in the middle of the American South.

This intricate Hindu temple is the largest of its kind outside of India itself and was constructed like a giant puzzle.

The largest cemetery in the American Southeast is a hidden gem near the heart of Atlanta.

The first singer to cut a country music record is buried in a small graveyard in Atlanta, Georgia.

The only subterranean ping pong table in Atlanta.