Fittingly, America's museum of architecture is itself a magnificently designed old building.

The romance of early commercial flight still fills this Art Deco destination.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

A town honors its legacy of traditional American Indian pipe carving with one gigantic pipe.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

What looks like a simple quaint estate in rural Pennsylvania was in the 18th century home to a small monastic community.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

A floating cat sanctuary on an Amsterdam canal.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

Historic medieval fortified city in southwest France.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Largest Roman Catholic church in North America.

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

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

Berkeley Springs State Park boasts the nation's only monument commemorating presidential bathing.

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

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

Outsider art meets paleontology at this roadside reptile repository.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.