Once the primary source of ice in this region during the mid-20th century.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

A Nessie-like monster supposedly lurks in this lake.

A line of blue paint marks the route of the inaugural parade.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

Perhaps the most scandalous statue of America's first president.

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

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

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

There’s a hidden military meme engraved on the World War II Memorial.

Home to items never before seen by the public.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.

These elusive, isolated rodents evolved into a distinct, locally iconic subspecies.

These red and black houses were awarded to the firefighters who saved their city from an enormous blaze.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

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

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

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

A monument celebrating the idea of reaching inaccessible places.

"We Seceded Where Others Failed."

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

The sign that drew attention to a young boy's cucumber stand is now the name of his fruit superstore.