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

The celebrated eyesore created by starry-eyed sweethearts.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Got apples?

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

Legend has it the commander of the defenders drew a fateful line in the dirt with his sword just before the final battle.

This soda factory is one of the last in America to use real cane sugar despite the protestations of Dr Pepper.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

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

A former major munitions plant that has been converted into a sprawling art space.

The only recreation of William Shakespeare's indoor playhouse.

At 207 feet, one of the world's longest continuous escalators.

An original apothecary from 1792.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

A nostalgic bibliographic gem.

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

Home to items never before seen by the public.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

The large rock formation where the Shawnee prophet Tenskwatawa stood and encouraged his warriors during the Battle of Tippecanoe.