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 innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

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

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

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

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

Washington's iconic carousel has a nice piece of Civil Rights history.

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

The most decorated dog of World War I is preserved in the Smithsonian.

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

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

Home to items never before seen by the public.

Las Vegas's very own 40-foot-tall fire-spewing praying mantis.

The second-largest gold nugget in existence, displayed in a Las Vegas casino conveniently named the Golden Nugget.

A piece of the iconic wall found an unlikely new home in a Vegas bathroom.

This incredible collection of vintage pinball machines can be played at 25 cents a pop.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.

The final resting place of the businessman-turned-astronomer who helped discover Pluto stands near his observatory.

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

One of the final grand railway depot hotel complexes is slowly being restored to its former glory.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.