A Turkish ghost town abandoned in a population exchange with Greece.

This famous city eluded concrete detection until the early 2000's.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

A marvel of Byzantine engineering under the streets of Istanbul.

Roman ruins top white travertine terraces formed by ancient hot springs.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The celebrated eyesore created by starry-eyed sweethearts.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

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

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

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

Washington's iconic carousel has a nice piece of Civil Rights history.

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

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

The "lovely red Vega" of the legendary record-settling pilot.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

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

This roadside attraction has been serving out its fair share of hearty folklore and chaos since 1858.