On the Hudson resides one of the largest clocks in the world.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.

A playground inspired by differential calculus dangles from the ceiling of the Liberty Science Center.

The drawbridge used in the filming of the movie 'Annie' has been in the open position as it was in the movie for decades.

An abandoned military bunker that has been transformed into an artist's paradise.

The real-life site of Ichabod Crane's infamous gourd attack.

This 19th-century clock has been restored to help withstand the harsh environment of its seaside home.

The absurd creation is a compulsory destination for selfies in Buffalo.

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

Art Deco stylings conceal the true nature of this bridge.

The fossilized remains of ancient California redwoods.

A huge collection of rocks, gems, and crystals.

This historic California cemetery holds the bodies of veterans of both the Civil War and the Donner Party.

A sculpture dedicated to Napa Valley's oldest mineral water company.

The largest drain hole in the world.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

One of the deadliest American air disasters is nearly forgotten in Brooklyn.

Michael Jackson got Bad and Crocodile Dundee walked on heads in this iconic Brooklyn subway station.

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

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

On the wall of this medieval walkway, a symbol of the Spanish Inquisition.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.