Researchers have discovered a now-dried tributary of the Nile that flowed to the great pyramid complex of Giza some 4,500 years ago.
The findings, published in the Proceedings of the National Academy of Sciences, explain how the ancient Egyptians were able to transport millions of tons of heavy building blocks to the site of the iconic pyramids over four miles of what is now a desert landscape. Business Insider.
The researchers concluded that the builders of the pyramids may have used a branch of the Nile River, now dry, to move construction materials.
"It was impossible to build the pyramids here without this branch of the Nile," study author and geographer Hader Sheesh told The New York Times.
Astounding in size, with perfect geometry and adorned with intricate decorations, the pyramids at Giza, on the outskirts of modern Cairo, served to demonstrate the power of the pharaohs in Egypt's golden age.
The site includes three pyramids and the Great Sphinx of Giza, built as ornate mausoleums for the pharaohs Khufu, Khafre and Menkaure around 2560 BC and 2540 BC.
Khufu's pyramid, known as the Great Pyramid, was the first to be built and the largest of the three. It includes about 2.3 million blocks of limestone and granite. Each block weighs between 2.5 and 15 tons.
The Great Pyramid is the oldest of the seven famous wonders of the ancient world and the only one that remains largely intact. It originally stood about 481 feet, making it the tallest man-made structure in the world for nearly 4,000 years.

However, the Nile is about four miles east of the pyramids. How the builders at that time managed to transport the huge blocks to the site of the construction of the pyramid has long puzzled scientists and archaeologists.
Scientists had previously thought that the Egyptians could have brought the stones to the country by water.
A papyrus discovered in 2013 showed the location of an ancient port near the Red Sea where the stones were loaded, suggesting the Egyptians knew how to move the blocks along rivers.
Other excavations have suggested that a port was built near the pyramids and that the builders carved intricate waterways near the port.
To determine whether the Nile followed a different route back then, scientists dug holes in the desert surrounding the pyramids looking for ancient pollen from plants like papyrus and cattails, which thrive in a watery environment.
The study showed that during the reigns of Khufu, Khafre and Menkaure, about 4,500 years ago, a stable branch of the Nile River extended towards the pyramids.
This branch of the Nile is now long gone. Pollen from drought-resistant plants such as grasses showed that this branch of the river had been dwindling for centuries by the time King Tutankhamun came to power, around 1350 BC, according to The Times.
"Knowing more about the environment may solve part of the pyramid-building puzzle," one researcher told the Times.