We often hear about the Inca, Maya, and Aztec, but I have never heard much about any large-scale, organized societies like that north of the Rio Grande. Do we know of any great cities and civilizations from time? If so, why isn't there the same kind of archaeological record of their societies? If not, is there any generally accepted reason why?
One that instantly springs to mind is Cahokia, which is in southern Illinois, basically across the river from St. Louis. It was the largest urban settlement of the Mississippian culture before European contact. In its heyday, somewhere between 1050 and 1300 CE, it was home to at most 40,000 people. But it was abandoned about 100 years before Columbus, and truthfully we're still not totally sure why.
The site is still there, Cahokia Mounds. It's a National Historic Site site so it's protected by the state of Illinois. It's still being excavated from time to time, but it's a fun visit if you're ever in the area.
I live 10 minutes from Cahokia, it's a great site and is on the world heritage list. They have a great free museum and you are able to go atop the largest mound which is stunning in its shear size and amount of earth that had to be moved via woven basket on the backs of workers. I highly recommend visiting for any history lover.