The pyramid of King Khufu, or Cheops, is one of the great wonders of the ancient world. It was built for King Khufu by his architect Hmiunu. It took him about 20 years to build the pyramid. He used about 2,300,000 blocks of stone to build it. The weight of each block of stone varied between 1.5 and 0.5 tons. The burial chamber is accessible through the Grand Gallery.
The pyramid was opened in the ninth century by the Caliph Al-Ma'mun. He could not find the real entrance so he forced a passage through the masonry to reach the interior. The pyramid and the sarcophagus were found empty. The purpose of the Great Pyramid of Khufu has been the subject of many theories. John Taylor, in 1859, believed, "The Great Pyramid has been built by a divinely chosen race of non-Egyptian invaders, acting directly under God's guidance". Rutherford, in Science of the Great Pyramid the Fourth, found, "The architect of the Great Pyramid is the same as that of the Universe and it is the divine plan that contains deep secrets of the eternal spirit".
Arab writers who associated the Pyramids with the Biblical narrative of Chaos believed, "The pyramids had been built as a result of a dream to serve as repositories for all the wisdom and scientific knowledge of the ancient Egyptians, which would otherwise have been lost". Julius Honorius, a pre-fifth century personage, quoted a legend that, "The pyramids were the Granaries of Joseph, which had been used for storing the wheat during the years of plenty". According to Proclus, "The pyramids were not only tombs and monuments, but they might have also been used as astronomical observatories".