Kinda reminds me of this sign that I saw, which was in Mexico, but clearly directed at us.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.perthscuba.com%2Fwp-content%2Fgallery%2Fcenotes-mexico%2Fperth-scuba-dive-mexico-cenotes_-3447.jpg&hash=84ca23068bae051f5ba4a0f7cdf0b0bd2f3b3a72)