A chilling disappearance (and rescue) of a child uncovers a geological mystery.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

These unusual rooms on wheels are holdovers from the 1960s.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

The "lovely red Vega" of the legendary record-settling pilot.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

A spiritual vortex among the red rocks in Sedona.

The largest and most well-preserved petroglyph site in the Verde Valley.

This sinkhole in the Arizona desert is filled with carbonated, arsenic-rich water

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world’s largest coastal brick fortresses.

A historic presidential getaway on the continental United States' southernmost island.

The museum chronicling a treasure hunter's dream, fulfilled.

A historic landmark and museum filled with curious objects representing the history of Key West.

The highway's southernmost spot is a beloved local attraction.

An idyllic swimming pool tells the tale of Hemingway's trouble with women.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

A monument celebrating the idea of reaching inaccessible places.

"We Seceded Where Others Failed."

Here’s how Robert the Doll earned his reputation as the most haunted doll in the world.

This spiny beast guards an artist's village while vying for the title of largest lobster in the world.