Under a playground is a little-known sealed train tunnel that likely contains the bodies of workers trapped by cave-ins.

This outdoor gallery of graffiti-covered walls pays homage to the past, present, and possible future of street art.

The famed amusement district marks the beginning of summer with a wild procession of nautical creatures.

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

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

This weeping, 10-foot-tall sculpture was a maquette for a 9/11 memorial.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

Just like the real 36th president of the United States, animatronic LBJ amuses visitors with jokes and stories.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

New York City's only radical feminist independent bookstore.

The California capital city once stood 10 feet lower than it does today.

This floating sculpture of ice is a poignant reminder of nature's power.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

Vacant Beaux-Arts buildings that serve as reminders of a beach town’s glory days.

Memorial to the 137 lives lost on a ship fire, the whole hulk of which washed up on the Asbury Park shore.

Marie told fortunes from her small stand on the Boardwalk for decades, including to a young Bruce Springsteen who would busk outside her booth.

This innocent-looking townhome is actually a subway exit.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

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

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

Home to items never before seen by the public.

A diminutive memorial marks the site of a successful assassination by a right-wing death squad in America's capital.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.