When I was a little, really little girl. I lived in Cahokia. For the life of me I don’t remember seeing these mounds. But there was a fresh spring water fountain that my Mom used to take me to. It was delicious.
There are still some small mounds in some state parks ( i.e. Perrot state park near Trempealeau, Wi). But near McGregor, Iowa is Effigy Mounds Nat. Monument where there are larger mounds.
I went to college in Cahokia.
There was an article about it in the 1960s, probably “Argosy” or “True” magazine (my dad subscribed), and as a consequence, during a family vacation, I climbed the thing. It was already being studied, but like most Precolumbian sites, it consisted of, well, a freakin’ mound of dirt. I would have preferred to have taken a station wagon trip to, say, Egypt or Greece, but they hadn’t put in the freeway yet. ;’)