The ruins of the first Spanish settlement in Puerto Rico.

Puerto Rico's oldest rum producer started its 140-year-old business with "a little barrel."

Puerto Rico's once thriving oil company is now an abandoned wonderland of rusty steel.

An artist’s underground sanctuary, 40 years in the making.

This community-driven organization uses education and eco-friendly technology to protect the environment.

This ''hidden'' 19th-century bridge played a simple, yet important role during the Spanish-American War.

An unnatural lake in a naturally beautiful setting.

This nearly abandoned "company town" is a ghost of Puerto Rico's once-lucrative sugar industry.

The abandoned remains of this once-thriving hotel looms over the city, awaiting an uncertain future.

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

This tiny home was originally a narrow alleyway.

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

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

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

Years of neglect and nature took a toll on this 19th-century lighthouse.

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

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

Rusting, graffiti-covered tanks litter the beach of this island, once used by the U.S. military for target practice.

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