With its webbed walls and bright red coloring, Calgary's iconic bridge looks like a finger trap puzzle stretched across the river.

A series of concentric circles represented a bold new experiment in socialist urban planning, and it notoriously difficult to get around.

The world's largest bicycle shelter can hold more than 12,500 two-wheelers.

The soaring gondola lines form the longest aerial cable car system in the world.

Planned as the world’s first zero-carbon city, it had lofty ideals—but is only 5 percent completed and aiming for 50 percent carbon-neutral.

The maze-like transportation hub contains abandoned areas, derelict stores, and a resident bat colony.

At just 25 inches at its narrowest point, it's one of the tightest streets in the world.

This abandoned viewing platform has become a monument to unnecessary government spending.

An oversized, oddly designed pedestrian overpass has drawn comparisons to a commode for pachyderms.

The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

A giant roundabout made up of six smaller roundabouts can befuddle the uninitiated.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.

The haunting peak of an old church is all that remains of a drowned Brazilian city.

With no menu and no sign, this 130-year-old taverna doles out affordable home cooking.

Hidden in the hills of Western Pennsylvania lies one of the best-kept ghost towns in America that you can legally visit.

The Bulgarian royal family exclusively used this ornate, now-abandoned train station.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

A gift to the children of Boston, this bronze bear represents playfulness, a spirit of love, and the warmth of big hugs.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

Plans for this peninsula included houses, the United Nations Headquarters, and a nuclear power plant. When none of them worked out, it became an expansive park.

MIT students continue the legacy of beloved professor "Doc" Edgerton through learning by doing.

Solar powered Spectacle Island features all-green facilities.

This tower commemorates the spot where George Washington hoisted the Grand Union flag.

Malcolm X's house during his most formative years faces an uncertain future.