The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

Cryptic messages embedded in the New York City sidewalk.

The notorious headquarters of a corrupt political machine.

Commemorating the spot where the famous scientist fed his pigeons.

One of the last few places in Manhattan that employed a pneumatic systemic keeps it on display.

Captain America, Sub-Mariner, and the Human Torch were all born in this art deco Manhattan masterpiece.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

A famous songsmith's custom piano, dubbed "High Society," is hidden just out of sight in one of New York's finest hotels.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

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

This chapel on a cliff is renowned for its healing powers and was founded on the site of a supposed divine intervention.