An abandoned munitions factory with a shot tower continues to wage war on the surrounding environment.

A castle built by an eccentric medieval enthusiast in suburban Ohio.

Dramatic river bend surrounds a natural red-rocked pedestal.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Tiki luxury on Nob Hill.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A psychedelic labyrinth on the San Francisco bay.

The most confusing clock in New York.

There must be a pun in this haystack somewhere...

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

A bit of retro transportation flair preserved in the world's largest department store.

A band of aerialists and circus performers putting on incredible shows in East Williamsburg.

Mysterious 500-year-old tapestries depict a unicorn hunt.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

Elevated freight railway turned wildly successful urban park.

The largest earthwork effigy in the world.

After a water tower painting was accused of being an ad, a simple fix was made that gave the city a motto.

An unusual, super-sized grocery adventure awaits in an Ohio suburb.

The largest ancient burial mound in Ohio.

Mussolini gave Cincinnati a bronze statue of Romulus and Remus suckling at a wolf's teats.