An abandoned railroad tunnel is now filled with bioluminescent bugs.

The second largest waterfall by volume in the U.S., Willamette Falls is outdone only by Niagara in the amount of water that is pushed northward.

Every color in the rainbow awaits.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

A hollow cement depiction of time's inexorable effect on the human body.

This spectacular track has run continuously since 1882.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

Hear the quietest sound from across the dome.

This floating garden in the sky is straight out of a fairy tale, but the real thing is nothing short of magical.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

The only diamond mine in the world where you can keep what you find.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

A common entry point to the Griffith Observatory trail holds its own wonders.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

The middle finger of modernity.

148 feet long and in the middle of a verdant forest.

One man's ambition created this psychedelic log home.