Scientists have found evidence of hydraulic engineering in the Step Pyramid of Djoser in Saqqara, Egypt, which is believed to be the oldest of the seven monumental pyramids and potentially constructed about 4,500 years ago. The hydraulic system could have moved the stone blocks forming the pyramid from the ground up, leading to a hydraulic elevation mechanism that could have lifted them into place. This discovery could help clarify the origin of hydraulic systems in ancient Egyptian pyramids. The researchers also found that a massive, unexplained, Saqqara structure, known as the Gisr el-Mudir enclosure, has features of a check dam designed to trap sediment and water. They believe this could have led to the construction of a temporary lake and a unified hydraulics system that improves water quality and regulates flow for practical purposes and human needs.