The spectacular Giza Pyramid Complex consists of three pyramids, including the Great Pyramid of Giza and the Sphinx, which are jointly known as the Necropolis. Located on the Giza Plateau on the outskirts of Cairo, it is also known as the Pyramid of Cheops or Pyramid of Khufu. Among the three Pyramids in the complex, Menkaure, Khafre and Khufu, the Great Pyramid or the Pyramid of Khufu, is the oldest, as well as the only one to remain largely intact. Considered as the most ancient among the Seven Wonders of the Ancient World, it is believed to be built 2560 BC as a tomb for the Fourth Dynasty Pharaoh Khufu or Cheops. According to the Egyptologists, it took about 10 to 20 years to complete the massive structure.
Khufu’s pyramid, considered many as the most striking colossal single structure ever erected on this planet, retained its glory as the tallest man-made structure in the world for more than 3500 years. It is estimated that, initially it was 481 feet (146.5 m) tall, but due to natural erosion combined with the absence of its capstone (pyramidion), its present height has come down to 455.4 feet (138.8 m).Originally, the outer surface of the structure was covered by smooth limestone casing stones, and after years of continuous erosion, the rough core structure became exposed. However, some of the casing stones that once covered the structure can still be found around the base. The outer casing and the inner passages of the pyramid were made of finer light-coloured limestone, while yellowish limestone blocks were used for the core. It is estimated that, to complete the enormous construction, approximately 2.3 million stone blocks, weighing an average of 2.5 to 15 tons each, were used. According to the accounts of Herodotus, the famous ancient Greek historian, about 100.000 persons took as long as twenty years to complete the construction of the Great Pyramid and more than 12 blocks of stone were needed to move each hour. About 8000 tons of granite were transported from Aswan, while 5.5 million tons of limestones that were used for the casing were transported across the river.
Originally the entrance to the Great Pyramid was on the north side, about 56 feet (17m) vertically above ground level. A descending passage, which followed the original entrance, ends in an unfinished underground chamber. However, today tourists enter the Great Pyramid through a tunnel, known as the ‘Robbers' Tunnel’, which was probably created around AD 820 by using a battering ram, which dislodged part of the ceiling stone of the descending passage to hide the entrance to the Ascending Passage.
The descending corridor, originated at the end of the original entrance, branched out to a further ascending narrow passageway, which finally leads to a room termed as the Queen’s Chamber and to a great slanting passage, called the Great Gallery. The Queen’s Chamber is located in a calculated manner, just at the halfway between the north and the south faces of the pyramid. The 28 feet (8.6 m) high and 153.1 feet (46.68 m) long Great Gallery, is actually a passageway that continues the slope of the ascending passage and finally leads to the proper burial chamber, known as the King’s Chamber.
The King's Chamber is 34.4 feet (10.47 m) from east to west and 17.17 feet (5.234 m) from north to south, with a flat roof 19 feet 2 inches (5.852 m) above the floor. The chamber is completely lined with granite. Above the floor there are two narrow shafts in the north and south walls, the exact purpose of which is really unknown. Some Egyptologists maintained that they were air shafts, built to serve the purpose of ventilation. However, today it is widely believed that the shafts were associated with some ritualistic purpose connected with the ascension of the king’s spirit to the heavens. Nine huge slabs of stone formed five compartments above the roof of the chamber, which are called the Relieving Chambers. Probably those were built with the intention to safeguard the King's Chamber from the possibility of a roof collapsing under the weight of stone above the Chamber. The King’s Chamber contains only one object, a rectangular granite sarcophagus, one corner of which is broken. A sarcophagus is a stone coffin, typically adorned with sculptures or inscriptions associated with the ancient civilizations.
Even today, the massive structure of the Great Pyramid is a debatable subject for the scholars. How those huge slabs of stone were transported to the working area and how the massive structure with towering height was built in those ancient days of human civilization is still an enigma. It is probably possible that the Egyptians utilized the service of a sloping and encircling embankment – made of brick, earth, and sand. It is also possible that those intelligent people increased the height and length of the embankment according to the increased height of the construction and finally, with the help of sledges, rollers, and levers, countless stone blocks were hauled up the ramp. However, nothing is sure. Among the numbers of theories and unknown numbers of ifs and buts, the method of construction of the gigantic structure is still shrouded in the clouds of mystery.
Recently, by the observation of ‘cosmic ray muons’, that are only partly absorbed by stone, the researchers discovered a ‘big void’ in the pyramid, which is an empty space of no less than 30 m long, that could be a possible hidden chamber.