Khmer Rouge's high security prison.

5,000 skulls in memorial to those killed by the Khmer Rouge.

Bombed and burned, this monument represents the often controversial ties between Vietnam and Cambodia.

One of the biggest markets in Asia, under one of the continent's largest domes.

The capital of Cambodia is named after the hill on which this ancient temple complex stands.

More than 100 Hindu temples are slowly being swallowed by the forest.

You can walk up Thailand’s naturally non-slip waterfall.

Vintage furniture and art share space with all manner of collectibles at this quirky shop in Bangkok.

This claimant to the title of "smallest church in the 48 states" doubles as an equally tiny, quasi-post office.

The grave of the iconic Kentucky Fried Chicken mascot features a bust of the man behind the goatee.

This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

Come for the speed, leave in love with the desert.

A 90-foot-tall psychedelic "tree" on the side of the highway has baffled passersby for decades.

A replica that won't float away.

An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

Jurassic Park—A Still Life.

The location along the shores of the Great Salt Lake of what was once called, "The Coney Island of the West", now sits barren due to arson and time.

The remains of this early 20th century refinery loom on a mountainside like a graffiti-covered fortress.

A museum dedicated to the alleged Roswell Incident.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

A unique geological area spiked with wind-carved rocks that resemble teepees.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

This wrecked airplane has been sitting on a black sand beach since the 1970s.

This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.