A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

Chicago's largest cemetery is full of beautiful Victorian monuments and more than a few ghost stories.

A haunting statue called "Eternal Silence" has quite the reputation among visitors with active imaginations.

An antiquated German apothecary on Chicago's North Side.

An enormous park-like oasis, full of famous Chicagoans’ graves.

A Bibliophile's Dream.

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.

Khmer Rouge's high security prison.

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

A former French military respite turned jungle tourism hotspot.

A battle between nature and architecture in the Cambodian jungle.

The largest Chinese cemetery in the world outside of China dates back to the 15th century.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

Hindu temple of the dead home to hundreds of long-tailed macaques.

More than 200 statues filled with cryptic symbols give this park spot an aura of horror vacui fantasy.

Believed to have once stored either human remains or rice wine, thousands of mysterious stone jars lie in ruin.

A mile-long navigable cave adorned with stalactites and stalagmites reaching up to 65 feet tall.

Bangkok celebrated its shifting monarchy with a militaristic homage to democracy.

Bizarre dirt trail winds a narrow path above the tree line.

Monkeys lounge around at this 13th century temple.

The headquarters of the Mahanikai school of Buddhism, Thailand's largest monastic order.