The 10th-tallest pyramid in the world, this former sports arena is now home to a massive Bass Pro Shops store.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

This Memphis recording studio launched the careers of Jerry Lee Lewis, Johnny Cash, and Elvis Presley.

This funicular railway rumbles along for a mile up the nearly vertical face of Chattanooga’s Lookout Mountain.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

An abandoned town is hidden in Great Smoky Mountains National Park.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

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

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

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.

An unnatural lake in a naturally beautiful setting.

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

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

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

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

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

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

This tiny home was originally a narrow alleyway.

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

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

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

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

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