This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

The site of the earliest colonial settlement in the Bahamas started as a place of religious refuge.

Lone survivor from Custer's Last Stand forever preserved.

A tiny racehorse graveyard in the middle of a quiet Kansas City suburb.

During the solar phenomenon "Lahaina Noon" this bendy, curvy sculpture forms a perfectly circular shadow on the ground.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

An ode to one of the first concerts broadcast via satellite.

The Denny Substation has been called "the coolest substation in the world" and sits in a densely populated Seattle neighborhood.

The ghostly remains of what was once the world's richest copper mine.

A battle between nature and architecture in the Cambodian jungle.

When the USA donated cement and funds to expand the airport in Laos, the Laotians built a massive monument instead.

What appears to be a wizard's lair in Milwaukee actually houses a massive water pipe.

Statue dedicated to the star of an old television show.

An off-the-beaten-path place to literally hang beneath Milwaukee's Holton Street Bridge.

A unique botanical garden housed in three giant geodesic domes.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

Before he was America’s most famous preservationist, John Muir was an ingenious mechanical inventor.

This unusual structure may be on its way to becoming a cultural landmark in Toronto.

This urban oasis is a marvelous meld of music and landscape architecture.

The artwork commemorates the many ways 20th-century people perished while on the clock.

The flock of plastic poultry is an ode to the classic comedy staple.