One of the bootprints left on the moon by Armstrong or Aldrin. The shape and tread of the boot is clearly visible. The lunar dust is a dull gray, and the boot made a deep enough impression that part of the imprint is in shadow.
https://files.mastodon.social/media_attachments/files/110/724/467/398/848/276/original/4c67600e926ab5f5.jpeg