The remains of a ruined mansion memorialize the 1906 earthquake.

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

Visible below the waves are memorials to the city's Gold Rush dead.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

A 140-year-old castle with underground caves hidden in San Francisco.

Originally a meeting place for foreign correspondents and war reporters, the FCC remains an atmospheric spot for sunset drinks in Phnom Penh.

The largest mosque in Cambodia was built to unite the country's Muslim community but soon sparked division and controversy instead.

Though it was originally dedicated to the Hindu god Shiva, Baphuon was converted to a Buddhist temple in the 15th century, complete with a massive hidden statue.

The river depicted in the antiwar film 'Apocalypse Now' was likely based on this Mekong tributary.

A secluded, little-known temple hidden amid the dense jungle.

A small 12th-century temple surrounded by waters believed to have curative properties.

An abandoned Cambodian resort that mirrored the downfall of the country as it was happening.

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

This impressive clifftop temple was once at the center of an international custody dispute.

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

This Cambodian riverbed is covered in ancient Hindu carvings both above and below the waters.

A former French military respite turned jungle tourism hotspot.

A battle between nature and architecture in the Cambodian jungle.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

The bones of an old zoo crumbling in the shadow of a new one.

A Michigan farm has hosted the fierce competition since 1974.