Cahokia, the largest of the settlements of the mississippian culture, is renowned for

Earthen mounds

The city of Cahokia was founded by Mississippian culture near the current day city of St. Louis, MO.

Cahokia is known for the large earthen mounds created by tribes of the Mississippian flood plains. The large mounds were used as burial sites as well as tributes to the gods of the Cahokian people. This large site is believed to be the center of Mississippian tribes living up and down the river and connected by their mound building culture.

Monks Mound, an enormous structure similar in size to the Great Pyramid of Giza

Explanation:

Monk's Mound was the center of Cahokia and its elaborate network of mounds.