CHAMPAIGN, ILLINOIS—The presence of a ceremonial road running through the center of Cahokia has been confirmed by Sarah Baires of the University of Illinois. She uncovered distinct layers of fill dirt that resembles other monuments at the site. Known as the Rattlesnake Causeway, the elevated earthen road stretches from the Grand Plaza through the center of the city, and ends in Rattlesnake Mound. Cahokia’s buildings and the causeway may all have been constructed to align with the lunar standstill, when the moon rises at its southernmost point in the sky, every 18.6 years. “Why would Cahokians have built this one kilometer-long earthen feature after they constructed everything else? To me, it makes much more sense that this was one of the foundational pieces of the Cahokian landscape,” she told Western Digs. Traces of the road were first uncovered in 1927, but some thought it may have been a natural feature or an early railroad bed.