13. Why There is a Dirty Brick in the Starry Main Concourse Ceiling

If you look up at the giant zodiac on the ceiling of the Main Concourse in Grand Central Terminal, you’ll find a small, dark patch of brick next to Cancer, the crab. This brick reveals what the station’s ceiling looked like before it was cleaned during the restoration project in 1998.

What made the brick so dirty? A very common myth says the grime is actually 70% nicotine and tar, thereby providing a great anti-smoking ad. However, according to the John Canning Company that restored the mural, “A detailed analysis of the dirt by scientists at McCrone Associates reported that the dirt and grime did not contain any nicotine or particles that could be attributed to cigar or cigarette smoke. The cause of the sometimes 2-inch thick grime was the decades of air pollutants – specifically car and truck exhaust, and the emissions soot and contaminants from industrial plants and apartment-building incinerators.” They say it was left in the restoration deliberately, as a reminder of the past.