I was walking through New York and found a couple of seemingly-abandoned liquid nitrogen tanks on the street. Except they weren't abandoned: they were full, making a very quiet hissing noise, and plumbed into... somewhere. I did a bit of research, and found out why they're really there. Thanks to David Bodycombe, who tipped me off to the tanks' existence: I was planning to go looking for them, but instead I just found them, casually sitting on the street corner, while I was headed to the Rockefeller Center...