Rare recess caves fill this unbelievably beautiful Ohio park.

A massive cave complex boasts some of the clearest water (and most charming bats) in the world.

This bridge over D.C.'s Rock Creek Park is sometimes called the "Buffalo Bridge" because of its four buffalo sculptures, which were cast from a single piece of bronze.

The tunnel under the Capitol Building where Congress takes out its trash.

The second seat of Nye County, still mostly a ghost town, has become a magnet for those looking to live "away from it all."

This rest area is also home to a remarkable petroglyph site.

Located in the remote Monitor Valley, this travertine bowl contains a scalding pool of water.

Many believe these images represent interstellar lifeforms.

Live long and prosper in Tennessee.

A waterfall rushing through a lush fern gully in Australia's Tarra-Bulga National Park.

The spherical grains of white quartz sand give every step on this Australian beach a distinctive sound.

A unique rock formation that only a few have managed to venture inside.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

Harder layers in colorful sandstone weather out as prominent “fins" and even more intricate and bizarre shapes.

An unusual slot canyon in the Aztec/Navajo Sandstone has a cross-section like an inverted old-fashioned keyhole.

Remarkably realistic Florida shoal bass "swim" inside this large globoid sculpture.

The humble home where the famous beat author lived briefly and wrote one of his most famous works.

Home to a giant switchblade and one of the world's largest collections of pocket knives, this museum is a cut above the rest.

This freshwater spring fills with 10,000 gallons of water per minute.

Petroglyphs, bird watching, and a 100-year-old Ranch in one location.

Along the old Route 66 is an abandoned trading post made from old telephone poles, built by a former circus clown.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

This collection of Wild West movie memorabilia also claims to hold some secrets of the Lost Dutchman's mine.

Monty Python fans will recognize this abandoned mine as the Cave of the Killer Rabbit of Caerbannog.