Though many were skeptical at first, these animal-specific routes across the Trans-Canada Highway have been a major conservation success.

In 1909, the steepest and most difficult piece of track on the Canadian Pacific Railway was replaced with a series of spiralling tunnels cut into the mountains.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

A renowned Civil War veteran, this Bald eagle now presides over the Wisconsin State Assembly.

Comprised of Spanish war cannons, this sculpture once graced the bow of a WWI warship.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

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

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.

The 28,000-year-old specimen is remarkably intact.

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

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

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

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

The rogue roots are gradually consuming some of the historic marble grave markers.

The romance of early commercial flight still fills this Art Deco destination.

An obelisk marks the farmhouse where the founder of Mormonism was born.

Two small markers remember the Alamo's feline protectors.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.

One of the first intercontinental ballistic missile sites in the United States.

Dedicated to the history of the 1,000 nuclear missiles that once covered the Great Plains.

A fitting attraction for the corn capital of the world.

Down the road from where the Wright brothers lifted off is another flight tribute practically hidden from sight in the woods.

Fake subway tiles were installed to cover a design that resembled the Confederate flag—it's unclear if the resemblance was intentional.