This famous Nevada gold mine, once a hotbed of Wild West shenanigans, is now open for tours.

An errant donkey ushered in a new era of mining in Nevada.

A modern day curiosity cabinet.

A museum, art project, and institution that demands we look at the world around us in a strange new way.

This jagged colossus of a building is mostly held together by an enormous concrete exoskeleton.

Once the center of power for the region's various factories.

According to legend, this structure was inspired by the Tower of Babel and built in a 19th-century industrialist's yard so he could walk his dogs without leaving home.

One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

Niagara Falls holds a special place in Nikola Tesla's history, so they put a statue on it.

A tunnel that brings more than a century of history to life from the deepest parts of the Niagara Gorge.

Even drowned in an ocean of toxic waste, the remnants of this Romanian village stand tall.

This psychedelic tourist trap is a leisurely descent into madness.

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

Hamburgers are intensely proud of their tunnel beneath the river.

This colorful creation wasn't always a welcome part of Toronto's Moccasin Trail Park.

In Hong Kong, a fairytale flower tunnel is hidden within the gardens of a public housing complex.

The romantic botanic tunnel feels like a well-kept secret.

A repurposed railway tunnel with otherworldly acoustic characteristics.

The U.K.'s first underground railway line is now a lively thoroughfare for runners and cyclists.

This former train tunnel is filled with lines from a poem crafted by Robert Louis Stevenson.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

Once a sewer culvert, this road tunnel now offers cyclists and pedestrians a subterranean stroll under the C&O Canal.

An abandoned railroad tunnel transformed into a creepy path for hikers and cyclists.

A honeycomb-like structure of interlocking shelves creates a beehive of books.