Sign up for CNN\u2019s Wonder Theory science newsletter.\u00a0<\/em>Explore the universe with news on fascinating discoveries, scientific advancements and more<\/em><\/a>.<\/em><\/p>\n For years, Egyptologists have hotly debated how the massive pyramids of ancient Egypt were built more than 4,000 years ago. Now, a team of engineers and geologists brings a new theory to the table \u2014 a hydraulic lift device that would have floated the heavy stones up through the middle of Egypt\u2019s oldest pyramid using stored water.<\/p>\n Ancient Egyptians built the\u00a0<\/strong>Step Pyramid<\/a>\u00a0for Pharaoh Djoser<\/a><\/span><\/span> in the 27th century BC, and it was the tallest structure at the time, coming in at about 62 meters (204 feet) tall. But how exactly the monument was erected, with a number of stones weighing in at 300 kilograms (about 661 pounds), has remained a centuries-old mystery, according to the study published Monday in the\u00a0journal PLOS One<\/a>.<\/p>\n \u201cMany detailed publications have discussed pyramid-building procedures and provided tangible elements, but these usually focus on more recent, better-documented, and smaller pyramids of the\u00a0Middle and New Kingdoms<\/a>\u00a0(1980 to 1075 BC),\u201d said lead author Dr. Xavier\u00a0Landreau, CEO of\u00a0Paleotechnic<\/a>, a privately owned research institute in Paris that studies ancient technologies.<\/p>\n \u201cThe techniques involved could include ramps, cranes, winches, toggle lifts, hoists, pivots, or a combination of these methods,\u201d he added in an email. \u201cBut what about the Old Kingdom pyramids (2675 to 2130 BC), which are much bigger?\u00a0While human strength and ramps may be the sole construction force for small structures, other techniques may have been used for large pyramids.\u201d<\/p>\n Using an interdisciplinary approach, the new paper was the first to report a system consistent with the Step Pyramid\u2019s internal architecture, the authors wrote.<\/p>\n A complex water treatment system drawing upon local resources would have allowed for a water-powered elevator within the pyramid\u2019s internal vertical shaft.\u00a0Some type of float would have raised the heavy stones up the middle of the pyramid, according to the study.<\/p>\n While the theory is an \u201cingenious solution,\u201d some Egyptologists aren\u2019t convinced, as a more widely believed theory is that the ancient Egyptians used ramps and haulage devices to put the heavy blocks in place, said Egyptologist Dr.\u00a0David Jeffreys, a retired senior lecturer in Egyptian archaeology at the University College London who was not involved with the study. Here\u2019s what experts have to say on the new theory.<\/p>\n By analyzing available data, including paleoclimatology, the study of ancient climates and archaeological data, the study team suggested that water from ancient streams flowed\u00a0<\/strong>from the\u00a0west of the\u00a0Saqq\u00e2ra plateau<\/a>\u00a0into a system of deep-water trenches and tunnels that surrounded the Step Pyramid.<\/p>\n The water also would have flowed into the Gisr el-Mudir \u2014 a rectangular limestone structure that is a massive 650 by 350 meters (2,133 feet by 1,148 feet) \u2014 which would have acted as a check dam. This device, which was previously thought to be a\u00a0fortress, a celebration arena or a cattle enclosure,\u00a0would control and store water from heavy floods, as well as filter out sediment and dirt so they would not clog the water passageways.<\/p>\nEgypt\u2019s desert was once savannah<\/h3>\n