If it hadn't been caught in time, a flaw in the design of this Manhattan skyscraper could have led to its collapse.

This outdoor gallery of sculptures along the East River was once a landfill.

This striking arch, one of the first architectural elements constructed in Prospect Park, was recently restored to its original glory.

This eclectic sculpture garden in Brooklyn, home to a bizarre collection of art, was once a run-down junkyard.

A remnant of the original World Trade Center complex continues to serve as a commuter gateway.

This controversial statue has migrated twice in its life.

The painter who popularized "bulls" and "bears" as symbols for the stock market didn't get a proper headstone for over a century.

The façade of this building looks like a bingo board, but it's really a giant clock by a famed graphic designer.

What was once a vast naval cemetery is now home to nesting birds and pollinating bees.

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

These ornate manhole covers were used for a now-forgotten purpose.

This Manhattan skyscraper is a reminder of the brief but glorious age of urban air taxis.

Twenty-three trees, each paired with a basalt stone, line a street in Chelsea, continuing an urban project started by German Fluxus artist Joseph Beuys.

This plot of old-growth forest is the largest surviving remnant of New York City's original woodland.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

A retired oil tanker now offering amazing views of New York City.

This morbid scene depicts the Darwinian drama of death on the African savannah.

This magnificent herd of stampeding elephants has been frozen in time for over a century.

One of the most dazzling dioramas at the American Museum of Natural History is also one of the oldest.

An eerie diorama that captures the majestic nature of a few prehistoric-looking beasts.

For almost a century, this East Village newsstand has served egg creams to beats, hippies, punks, and everything in between.

The highest rapid transit station in the world.

This beautiful Brooklyn monument over a crypt memorializes a grim and largely unknown story from the American Revolution.

Those belting out show tunes might not realize this piano bar marks the site where Thomas Paine died in 1809.