I read somewhere (Atlas Obscura?) that there are some hollow sidewalks in NYC, and the sidewalk-adjacent property owners pay for the real estate underneath. To

I read somewhere (Atlas Obscura?) that there are some hollow sidewalks in NYC, and the sidewalk-adjacent property owners pay for the real estate underneath. To get around this, some owners have sealed off access from their building to the sub-sidewalk spaces, leaving closed off, empty chambers.