The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

The legendary building that needed ghostly approval before being built.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

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

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

An overlooked memorial honoring the local Washington residents who died in World War I.

A line of blue paint marks the route of the inaugural parade.

Every drop of D.C. tap water flows through this old waterworks.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

A portal into the bricked up canal that runs through the heart of Washington D.C.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

When it comes to handsignals (and colonialism) rock always beats scissors.

The span is crooked and made from two older recycled bridges.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

The most accurate timepiece in the world.

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.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

The site of the climactic scene from the classic horror film is now a historic landmark.