Secret to Great Pyramid's Near Perfect Alignment                  Possibly Found

The Great Pyramid of Giza was built about 4,500 years ago.
Credit: Mikhail Nekrasov/Shutterstock

Though slightly lopsided, the towering, Great Pyramid of Giza is an ancient feat of engineering, and now an archaeologist has figured out how the Egyptians may have aligned the monument almost perfectly along the cardinal points, north-south-east-west — they may have used the fall equinox.

The fall equinox occurs halfway between the summer and winter solstices, when Earth's tilt is such that the length of the day and nightare almost the same. 

About 4,500 years ago, Egyptian pharaoh Khufu had the Great Pyramid of Giza constructed; it is the largest of the three pyramids — now standing about 455 feet (138 meters) tall — on the Giza Plateau and was considered a "wonder of the world" by ancient writers. [In Photos: Looking Inside the Great Pyramid of Giza]