This block in downtown Brooklyn was a hotbed of antislavery activism along the Underground Railroad.

The gilded vestiges of a sterling department store can still be found in a Brooklyn shopping center.

Brooklyn's most iconic restaurant, resurrected.

Leaf through over 30,000 artists' sketchbooks in what may be the world's largest collection of doodles

This anonymous businessman sculpted in bronze became an enduring memorial after 9/11, and had been mistaken by rescue workers for a survivor in the rubble.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

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

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

The home of the first American-born saint is one of the only curved buildings in New York.

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

Unrepaired walls from a 1920 anarchist bomb attack.

Where now stands a 42-story condominium tower of marble, glass and steel was once the central market of New York’s slave trade.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

Possible relics of the ancient Roman city are hidden in this restaurant's façade.

A hidden "place of interment for gentlemen."

The artist and New York City icon lived, worked and died in this converted carriage house owned by another iconic artist, Andy Warhol.

These historic buildings once housed the headquarters of one of the most infamous gangs of New York.

A flooded Mexican cave that hides a river beneath the water.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

There aren't too many operational funiculars around, but Pittsburgh has two!

Meet your friends, marry your true love, or tell your enemies to kiss your butt under this historic Pittsburgh timepiece.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

A beautiful bamboo trail tucked in this famous Japanese Shrine.