The 25-million-year-old cavities have perplexed people for decades.

This abandoned railroad tunnel is now home to a micro-colony of bats and a ghost train.

A stray meteor left this picturesque hole in the Australian outback.

Prehistoric park filled with the fossils of dozens of extinct species including Australian megafauna.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

An Australian lake whose pink hue defies scientific explanation.

White cockroaches and other cave species occupy this massive series of lava tubes.

A castle hand-built by a Spanish dreamer in the Australian tropical jungle.

A collection of outdoor mystical statues paying homage to indigenous Australians and ecological stewardship.

A beautiful, but toxic, lake formed by mining.

Tribute to the Chinese people of Young and Australia.

Clusters of huge boulders in the Australian Outback.

Australian Lake set aglow by Noctiluca Scintillans.

Relics of Australia's convict past, and a modern scene of unimaginable horror.

Dilapidated ruins that once treated a notorious young serial killer, currently hosting vandals, squatters, and ghost hunters.

This eccentric cave dwelling is bizarre even by the standards of a subterranean town.

This shrine to film's most iconic wasteland wanderer is located in the very outback where the movies were shot.

Visitors can swim with vicious predators in Crocosaurus Cove's plastic daredevil enclosure.

The UFO capital of Australia is the outback’s answer to Roswell.

This dramatic sea spire is home to the world's rarest insect and is part of the lost continent of Zealandia.

This once-booming gold mining hub was basically abandoned overnight.

A perfectly preserved abandoned criminal asylum in South Australia.

This pioneer village is like a time capsule of 19th-century Australia.

It's home to the taxidermy remains of Peter, the dog who helped convict a murderer.