I only learned of the existence of this marker a few years ago, despite having lived in New York City for the past forty years, and saw it for the first time today.
It marks the place where Peter Minuit allegedly purchased Manhattan Island in 1626, though there's not really any evidence that this happened, or that if it did, it happened here. But it is certain that there was a giant tulip tree here that was hundreds of years old when it was felled by a storm in the 1930's.
It's in Inwood Hill Park, at the very northern tip of Manhattan Island, one more place that I would probably never have visited if I hadn't bought a car. I will definitely be back.