It's hard to believe the dizzying patterns covering this abandoned mine are completely natural.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

The ruins of the "20-year town" lay out among the mountains of Alberta.

Odd outsider art installations surround a Gold Rush-era ghost town.

A series of five defunct panopticon prisons in Cuba.

A deserted hodgepodge of experimental structures designed by nearby university students.

The “City of Stairs” sits high in the Andes, above the world’s largest underground copper mine.

This abandoned Antarctic research station is a Soviet ghost frozen in time.

An abandoned vacation home spent a decade taking on legends. It's now taking on water.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

This abandoned fishing settlement may well be the greenest village in the world.

An abandoned outdoor movie theater in the Sinai desert.

A haunted hot springs hotel that went from healing retreat to asylum before it was restored.

These mouldering mansion ruins remember a time when the Catskills were nothing but luxury.

The walkable ruins of an 19th century hotel, destroyed in a horse cremation gone wrong.

Built by the inventor of the radio, this abandoned hotel has housed early radio employees, military men, and a dangerous cult.

The ruins of a Florida miracle spring resort make it seem like a wonder that this was ever a health spa.

The top of society once luxuriated in this world-class hotel, which continues to impress, even in ruin.

A once-luxurious, now abandoned hotel in the Italian Alps.

This magnificent abandoned hotel has long been haunted by its Nazi past.

The abandoned remains of this once-thriving hotel looms over the city, awaiting an uncertain future.

The decaying remains of a once-luxurious Soviet spa town.

This eerie abandoned building with a dark history is said to be one of the most haunted places in the Philippines.

An abandoned resort in North Macedonia is a relic from the Communist Party of Yugoslavia.