Long before the city of St. Louis existed and even before any European explorers set foot in America, people populated the Metropolitan area. The Modoc Rock Shelter, a National Historic Site, is one area along the Mississippi River bluffs in Randolph County Illinois, where 9,000 years ago early Native American hunters and families used the bluffs as shelter against the elements. The bluffs run along the edge of the American Bottoms, the rich fertile flood plain on the east side of the Mississippi River.
Other evidence of the early inhabitants of the St Louis area is memorialized by the legendary Piasa Bird painted on the bluffs near Alton Illinois. The original picture of the Piasa Bird was etched into the bluffs near Piasa creek and was first observed by the French explorers Pere Jacques Marquette and Louis Joliet on their exploration trip from Canada down the Mississippi River in 1673.
Cahokia Mounds, in Collinsville Illinois, located across the Mississippi River from St. Louis and a State Historic Site, is another early Native American site and was settled about 650 AD. The ancient people of Cahokia left no written records, but archaeologists have found pottery, stone, shell, copper and wood artifacts that give clues to the nature of the people that once lived there. What is very obvious to visitors is that the people of Cahokia were mound builders. Monk's Mound, the largest of the 80 mounds at the site, is also the largest earthen man-made mound in North and South America. Cahokia Mounds is a National Historic Landmark and a World Heritage Site.
St. Louis also had its fair share of mounds and was originally called Mound City because of those mounds. As the city expanded, the mounds were removed and only one has survived, Sugar Loaf Mound, in South St Louis city. The mound was purchased by the Osage Nation in August 2009 with the intent to preserve the historical value of the mound.