Redditor randomlyassigned20 bought a house that's around 100 years old. He found a feature underneath the house that has him stumped, and he posted three pictures. Normally, the folks at the Old Houses subreddit are pretty helpful, and indeed some guessed it was for salt storage, or ice storage, or the ash clean-out for a previous chimney. But the rest of the comment forum leaned into another story altogether.
There are dozens more of these. Even randomlyassigned20 got into the humor of it. When the same pictures were posted to the Century Homes subreddit, the consensus was that this is an ash clean-out with a coal chute to the right. There's no chimney in that spot, but many old houses, including mine, had more chimneys back when fireplaces were the only heat source, which were later removed when central heating systems were introduced. But even that post still had jokes about Canadian hieroglyphs. Sometimes you just have to roll with the joke.