There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

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

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

Home to items never before seen by the public.

The lesser-known lost colony of Roanoke was a safe haven for formerly enslaved people during the Civil War.

Developed by focused shutterbugs, this museum exposes visitors to more than 6,000 different cameras.

This collection of over 50 classic pinball machines awaits visitors to downtown Roanoke.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

A unique book shop with a collection of rare tomes and a nostalgia museum.

148 feet long and in the middle of a verdant forest.

It may look like no more than a full-scale model, but every part of this full Space Shuttle stack had a working role in aviation history.

A propulsion engine testbed that paved the way for the Space Shuttle launch sits without recognition at this rocket center.

Famous for its bio-luminescent inhabitants, known as "Dismalites" .

A rusted metal giant pays tribute to Birmingham’s industrial past.

A massive tribute to this small county's top agricultural product.

The third tallest lighthouse in America once guided author Stephen Crane to safety.

A building so large that it has its own weather.

Florida's first suspension bridge.

You can walk through the first Boeing Air Force One, which famously carried JFK's casket from Dallas back to D.C.

One-of-a-kind museum inside the first Boeing 747-400 ever made.

The record holder for the world’s largest peach.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

This historical air terminal in Houston is slowly becoming an aviation museum dedicated to the city's aeronautical history.

The secret city built by the Manhattan Project.