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I went to Pompeii today, and learned that they used to mark the roads with “arrows” directing men to the nearest brothels. There were several of these throughout the city(r/pics)
Classicist here: ITT, a ton of myths perpetrated by tour guides on unsuspecting tourists who can’t be expected to know any better. The phalli are not arrows to brothels, no archaeologist believes that. The phallus was an incredibly common symbol of good luck with very little of the sexual connotation that we view it with today. It is shocking to us because we are viewing it with a puritanical post-Christian mindset, it would be quite mundane for a Roman. There are dozens of these around the city, pointing to buildings that are quite obviously not brothels.
Nor are the sexual wall-paintings a “menu”. Sexual wall-paintings are found in cubicula (rooms that can be locked) in homes that are clearly not brothels. Again, it is fun to believe the Romans to be an incredibly sex-driven hedonist society, but this is not the case, they just had very different aesthetic tastes than most modern societies.
If you want to read further on these matters, and have your information at the hands of scholars rather than tour guides who profit most by giving the juiciest folklore, check out The Fires of Vesuvius by Mary Beard, head of Classics at Cambridge.