<p>Cahokia Mounds historic site is just across the river from St. Louis. They have a very nice museum/visitors’ center, and I think you can walk on top of some of the mounds. It was the site of a thriving Native American city – in 1250, its population was greater than that of London!</p>
<p>"Cahokia was the most important center for the peoples known today as Mississippians. Their settlements ranged across what is now the Midwest, Eastern, and Southeastern United States. Cahokia was located in a strategic position near the confluence of the Mississippi, Missouri and Illinois rivers. It maintained trade links with communities as far away as the Great Lakes to the north and the Gulf Coast to the south, trading in such exotic items as copper, Mill Creek chert,[14] and whelk shells. Mississippian culture pottery and stone tools in the Cahokian style were found at the Silvernale site near Red Wing, Minnesota, and materials and trade goods from Pennsylvania, the Gulf Coast and Lake Superior have been excavated at Cahokia.</p>
<p>At the high point of its development, Cahokia was the largest urban center north of the great Mesoamerican cities in Mexico. Although it was home to only about 1,000 people before ca. 1050, its population grew explosively after that date. Archaeologists estimate the city’s population at between 8,000 and 40,000 at its peak, with more people living in outlying farming villages that supplied the main urban center. In 1250, its population was larger than that of London, England.</p>
<p>If the highest population estimates are correct, Cahokia was larger than any subsequent city in the United States until about 1800, when Philadelphia’s population grew beyond 40,000." [Cahokia</a> - Wikipedia, the free encyclopedia](<a href=“http://en.wikipedia.org/wiki/Cahokia]Cahokia”>Cahokia - Wikipedia)</p>
<p>If you go to the Arch in St. Louis, you can watch (for a fee) a movie about the building of the Arch - fascinating!</p>
<p>If you go to Hannibal, the Mark Twain cave (the cave he wrote about in Tom Sawyer, where Tom and Becky got lost) is pretty cool (both literally and figuratively!) I think Hannibal still has its wonderful arts and heritage festival in the fall.</p>
<p>While in St. Louis, almost everything is free! (paid for by a cultural district tax) The Zoo, Art Museum, Science Center, the museum of Westward Expansion under the Arch – all free! There is also a very wonderful Botanical Garden, not free.</p>