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

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.

At this studio, musicians, engineers, and quite possibly a music-loving ghost carry on Puerto Rico's musical traditions.

La Cara del Indio honors the Taíno chief who fought bravely against the Spanish invasion of Puerto Rico.

This rock in the middle of a river in Jayuya contains dozens of Pre-Columbian Taíno petroglyphs.

This beach pool offers a spectacle of crashing waves, blue hues, and a historical lighthouse.

Enjoy the waters of this half-moon-shaped natural pool surrounded by breathtaking scenery.

This colorful gate stands as an entrance to the walled city of Old San Juan.

Archaeological sites and great food inside the island's largest mangrove forest.

This beachside town is home to a diverse nature reserve, multiple cays, and one of the three bioluminescent bays in Puerto Rico.

This former railroad bridge was named after the great river that once flowed below it.

Drift through underground caves on a tube.

Invading U.S. troops were first seen from this now-abandoned tower, leading to the Spanish-American War.

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

An unnatural lake in a naturally beautiful setting.

The crumbling remnants of this 19th-century quarantine hospital hint at the touristy island's darker past.

This small fort played a huge role defending Puerto Rico’s capital city.

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

The highest peak in Puerto Rico is home to a rare fern that can only be found on six trees at its summit.

On this Puerto Rican island, many abandoned naval ammunition bunkers sit open while a few have been padlocked by locals as personal storage.

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

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

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

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