Places Gray Wants to Go

The longest navigable underground river in the United States is home to countless blind and albino animals.

This massive redwood tree has a hole in the base big enough to drive through.

Legends surround this jagged rock formation in the New Mexico desert.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

Treehouse motel and treehouse-building school.

Behind a bodega is a small museum of relics and ephemera showcasing the history of New York.

Hidden beneath a bridge, this waterfall is known for the large amounts of graffiti painted on its base.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

Yale University's home for rare works, including the mysterious Voynich Manuscript.

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

A whimsical village of unique treehouses resides in a Washington forest.

The largest permanent Monopoly board makes one of the longest games even bigger.

The longest living non-clonal organisms on Earth.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

Mysterious ancient boulder carved with petroglyphs in the mountains of Western North Carolina.

The subtle science of a master molecular gastronomist.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

The largest drain hole in the world.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

This free, take-a-book shop seems like a trick but isn't.

A little piece of the Shire is hidden behind a plant nursery in Port Orchard, Washington.

The world's oldest individual clonal tree looks like a wimp despite standing tall for 9,550 years.