The caldera of this mini-volcano has been turned into a naturally heated mud bath.

A cozy bookstore and coffee shop in the heart of Cartagena's Old City.

The most visited, and possibly most controversial, museum in Germany.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

Piran’s oldest square is laden with history and a beautiful 18th-century reservoir.

This one-time health resort was used by aristocrats around the world.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

A second generation sun-powered marvel lights up the night.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

A glittering South Asian anomaly in a wealthy Los Angeles suburb.

Scores of vintage street lamps shine along L.A.’s Miracle Mile.

This black shoreline is made up of exploded lava particles.

A series of waterfalls and pools that flow through the 'Ohe'o Gulch and into the ocean.

A tunnel of hardened lava along Maui’s famous Road to Hana.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

Climbing this abandoned railway leads to breathtaking vistas of O‘ahu.

A unique set of caves that spits waves back out into the ocean.

This saltwater swimming pool, which is the last of its kind in the United States, is slowly crumbling within sight of multiple high-end beachside hotels.

An authentic replica of an Asian temple and garden hidden amongst the natural beauty of Hawai'i.

An ode to one of the first concerts broadcast via satellite.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

Once the site of the Hawaiian monarchy, this building was originally designed as a palace.

Hawaii’s largest cemetery rests inside an extinct volcano crater.