For centuries, the Great Pyramid of Giza has been perceived as a four-sided structure. However, a 1940 aerial photograph unveiled a subtle concavity in the center of each side, revealing that the pyramid is actually an eight-sided figure. This unique feature, virtually invisible from ground level, becomes apparent only under specific lighting conditions, such as those during sunrise, sunset, or from an aerial view.
British astronomer Flinders Petrie had previously noted irregularities in the pyramid's walls in the 19th century. However, the means to definitively confirm his observations were not available at the time. The discovery in 1940 by a British Air Force pilot, P. Groves, provided the first visual evidence of this concavity.
The purpose behind this design remains an enigma. Some theories suggest it was an intentional design feature, potentially serving as a structural reinforcement to help the pyramid withstand earthquakes and erosion. Another theory posits that the concavity was meant to be seen from the sky, aligning with the Egyptians' practice of aligning monuments with astronomical events. The Great Pyramid's hidden eight sides continue to fascinate researchers, highlighting the advanced engineering and geometrical knowledge of the ancient Egyptians.