The Cahokia Mounds State Historic Site is already a National Historic Landmark and a World Heritage Site. Now, there's an effort to elevate the status of an area running through Collinsville Illinois to a National Monument.
For a couple of years, the National Park Service has surveyed the St. Louis area Cahokia Mounds.
Now, U.S. Senator Dick Durbin, an Illinois Democrat, is asking that a portion of the 4,000 acres become part of the park system. In a letter to President Barack Obama, Durbin writes that some of the mounds have protections, thanks to Illinois' burial law and the national landmark designation.
But he says that "many other mound sites-privately and publicly owned-are threatened as new roads are built and development" encroaches.
The mounds are huge humps that Native Americans made and in places still swell up from the ground. The state's historic site features remnants of one of the first cities in the Western Hemisphere. In 1250 AD, Cahokia was larger than London today.