- [Did the so-called mound builders of the United States have a lingua franca? Do we know what cultural traits or archaeological traits they shared between the various locations in which we have history of their dwellings and how closely related they were?](https://www.reddit.com/r/AskHistorians/comments/upueap/did_the_socalled_mound_builders_of_the_united/) is a really good summary of American mound builders that does a lot with Native American history (including their early (pre-maize) agriculture) and how mounds predate Stonehenge. My main interest is because of Cahokia, which I visited when meeting my husband's family.