The wooden airship was the largest flying boat ever built.

One of the largest aviation events in the world brings half a million aircraft enthusiasts to Wisconsin each year.

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

The contents of this safe survived a 37-kiloton nuclear bomb.

The largest man-made crater in the U.S. marks the spot where we once tested mining with nukes.

A picture-perfect town, perfect for blowing up.

If you want to take a peek at Area 51, this is legally as close as you're going to get.

An eatery for UFO seekers on the Extraterrestrial Highway.

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

Home to items never before seen by the public.

A herd of colorfully painted bovine statues can be found in the middle of "cowtown."

With its webbed walls and bright red coloring, Calgary's iconic bridge looks like a finger trap puzzle stretched across the river.

The New Central Library is a masterpiece of contemporary architecture in the midst of downtown Calgary.

This underground power plant looks more like a super-villian's lair than a public work.

This decommissioned DC-3 now forever points into the oncoming wind.

This First Nations monument is a peaceful spot with vast views of the Calgary prairie.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This Cold War missile launch site has been abandoned for 40 years.

A forgotten Cold War relic hidden in the outskirts of a Wisconsin city.

Live long and prosper in Vulcan, Alberta.

This massive and unusual rock formation near Okotoks is the world's largest known glacial erratic.

The large fjord lake is thought to be the home of "Ogopogo," a giant sea serpent.

Canadian centennial project designed to gather information about UFOs.