Van Cortlandt Park Monoliths, 6089-6115 Broadway, Bronx, New York, USA

These mysterious-looking monoliths can be found when strolling in Van Cortlandt Park in the Bronx. Made of a variety of different stone and evenly spaced, they look like some kind of ancient monument, except for the modern graffiti. It turns out there is no mystery surrounding them as they are related to a construction project. It was used as stone samples when planning the Grand Central Terminal over 100 years ago.