A deadly ancient portal to the underworld.

Flames have been burning within this mountain for more than 2,500 years.

The once highest point in China blends symbolic design with a kick of adrenaline.

The ruins of this prominent glass factory yield hidden treasures buried among the jungle floor.

This extravagant villa built by a Burmese merchant is part pagoda and part European mansion.

An eerie abandoned gentlemen's club built for British officials during the colonial era.

Vast stretch of tide-pools with a unique Moroccan charm.

The oldest monument in Marrakesh and the city's only surviving example of Almoravid architecture.

The former home of Dutch anthropologist Bert Flint now houses a collection of Berber art and artifacts.

Hundreds of wooden coffins dangle from cliffs and caves in the Philippines.

Smoked mummies housed in mountainside caves.

This curious fresh and salt water lake holds a secret that draws in deep divers from around the world.

Giant money stones of Yap.

These ancient monoliths make up one of the largest archaeological sites in Palau.

An isolated dive site teeming with cnidarians.

This mile-wide crater high in the mountains of Indonesia is the largest gold mine in the world.

The unique design was created by the traditional way communal rice paddies were divided among the indigenous people.

These 40,000-year-old stenciled hands are older than the famous cave art in France and Spain.

Explore a uniquely pristine Borneo forest, now protected by former headhunters turned tour guides.

Island, once a pirate hideout, now home to an abandoned resort.

The deepest hole drilled in the name of science, where evidence of Precambrian life was found.

These circular ruins are all that remain of a 17th-century Arctic whaling outpost.

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

In Phetchaburi, Thailand, a roadside vendor cooks his fare with 1,000 mirrors and the power of the sun.