TRUJILLO, PERU—According to a Live Science report, Gabriel Prieto of the University of Florida suggests that a six-mile-long, eight-foot-tall earthen wall built across two dry riverbeds in northern Peru may have been built by the Chimú people to protect their lands from El Niño floodwaters. It had been previously suggested that the wall, which is known as the Muralla La Cumbre, may have been constructed by the Chimú as a defense against invasion by the Inca. “The annual rainfall there in a regular year is very low—almost no rain at all,” Prieto said. “So when the rainfall was very high, that caused a lot of damage.” Prieto and his colleagues radiocarbon dated layers of sediment in the wall, and found that the lowest ones were laid down around A.D. 1100, soon after a large El Niño flood event. They also identified flood sediments on the eastern side of the wall, indicating that it could have protected farmlands and the capital of Chan Chan to the west. Prieto also thinks that evidence for child sacrifice uncovered at Chimú sites may be linked to the recurring El Niño danger. To read about excavations at Chan Chan, go to "Peru's Great Urban Experiment."