This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

The fifth-longest natural arch in the world, and the longest outside China.

This site is home to ancient petroglyphs and pictographs dating back to 6,000 B.C.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

The largest wildlife crossing in Utah allows local fauna to safely traverse the six-lane Interstate 80 at Parleys Canyon.

This geothermal hot spring hides beneath a slowly growing mineral dome.

The air force base preserves its scars from the Japanese attack on Pearl Harbor.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

Once the site of the Hawaiian monarchy, this building was originally designed as a palace.

This WWII plane died a quiet death, and is now a garden eel playground.

A glass display case holds the document that ended the Second World War—which one person signed on the wrong line.

This monument built by Japanese American immigrants spent decades underground.

This blowhole is supposedly caused by a trapped monster.

This statue of the "father of television" stands prominently in the United States Capitol.

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

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

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.

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

An overlooked memorial honoring the local Washington residents who died in World War I.

This grave marks the passing of a historic Jane Doe whose identity remains a mystery to this day.

Dine like an American revolutionary at Colonial Williamsburg.

Affectionately known as "Lord Bot," this historic statue has a cult social media following and rightly claims to be “the most metal inhabitant of the Wren Yard.”