An ancient gathering place
In the floodplain of Louisiana's Ouachita River lies an arrangement of earthworks that changed our understanding of early human societies in North America. Known as Watson Brake, the site consists of eleven mounds connected by earthen ridges to form a large oval, about 280 meters (920 feet) across. Radiocarbon dating of the site's layers shows that its construction began around 3500 BCE and continued for approximately 500 to 700 years. This makes Watson Brake older than both Stonehenge's main phase and the Great Pyramid of Giza.
The mounds themselves vary in size. The largest, Mound A, stands over 7.5 meters (25 feet) tall, while others are as low as 50 centimeters. The construction was incremental, with evidence of multiple building stages. On some mounds, work stopped for long enough that soil layers had time to form before the next phase of building began. The second-largest mound, Mound E, appears to have been built in a single, continuous effort. The central area enclosed by the mounds and ridges was kept clean of the usual debris of daily life, suggesting it was used as a communal or ritual space.
Life without agriculture
The people who built Watson Brake belonged to the Evans culture, a society of hunter-gatherers. Archaeological evidence shows they lived on a diet of aquatic resources. They consumed large quantities of fish, including freshwater drum and catfish, along with turtles and mussels. This was supplemented with deer, raccoon, turkey, and various nuts and fruits from the surrounding floodplain and upland forests. They cooked using heated clusters of local gravel, a technique that predates the invention of pottery.
The existence of Watson Brake shows that a society did not need agriculture or a permanent, centralized hierarchy to create large-scale, monumental architecture. The builders used locally sourced materials and tools made of stone and bone. Distinctive projectile points, known as Evans points, are found at the site. Archaeologists also discovered tiny stone microdrills, likely used for making beads from small pebbles. After centuries of use, the site was abandoned around 2800 BCE. The reason for the abandonment is unknown, but one theory suggests a shift in the course of the nearby Arkansas River may have altered the local environment, making it less resourceful.