The international “ScanPyramids” project has discovered a nine-meter-long and 2.10-meter-wide corridor behind the Great Pyramid of Giza, known as Khufu Pyramid. The discovery was made using non-destructive surveying techniques and is expected to lead to further findings. The passage was likely designed to relieve the weight of the 4,500-year-old Khufu Pyramid. The discovery has been described as the most important scientific finding of the 21st century and has the potential to provide valuable insights into ancient Egyptian construction techniques and engineering knowledge.