The famous artist couple lived and worked here, in two different houses connected by a bridge.

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

An Industrial Revolution-era public work that purified water using nothing but sand.

Rochester's signature culinary delicacy.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

A speck of nature and art in one of San Francisco’s most notorious neighborhoods.

A pair of mutilated bronze octopuses slump at the base of the monument honoring California's admission to the U.S.

A rare wayfinding portmanteau of “Street” and “Avenue.”

Spanning an elevation of 160 feet and containing 388 steps, this is Seattle's longest staircase.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

Speak to a companion on the other side of the room loud and clear through this architectural anomaly.

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

Thousands of crosses and markers for soldiers who lost their lives in Iraq and Afghanistan blanket a California hillside.

Ship skeletons haunt Baltimore's waterways.

A collection of artifacts from Maryland's maritime past.

This Upper East Side apartment co-op was designed as a tuberculosis sanitarium.

This futuristic airport terminal was abandoned for decades before reopening as a hotel—with a vintage plane of its own parked out back.

The ballpark in "Pigtown" where the Brooklyn Dodgers made their name was replaced with a huge apartment complex.

This wall on a street corner in Lower Manhattan has been a blank canvas for a rotation of renowned artists since the 1980s.

A derelict bit of transportation infrastructure hidden in the woods.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

A swimming hole in the historic industrial quarry that supplied the marble for the Baltimore Washington Monument.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.