With nickel-steel armor and three-inch thick bullet resistant windows, FDR's train was a rolling fortress.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

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

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

More gold than anywhere else, ever.