Arcitecture

The Great Pyramid of Giza (also called the Pyramid of Khufu and the Pyramid of Cheops) is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact. Egyptologists believe that the pyramid was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu (Cheops in Greek) and constructed over a 14 to 20-year period concluding around 2560 BC. Initially at 146.5 metres (480.6 ft), the Great Pyramid was the tallest man-made structure in the world for over 3,800 years, the longest period of time ever held for such a record. Originally, the Great Pyramid was covered by casing stones that formed a smooth outer surface; what is seen today is the underlying core structure. Some of the casing stones that once covered the structure can still be seen around the base. There have been varying scientific and alternative theories about the Great Pyramid's construction techniques. Most accepted construction hypotheses are based on the idea that it was built by moving huge stones from a quarry and dragging and lifting them into place.

There are three known chambers inside the Great Pyramid. The lowest chamber is cut into the bedrock upon which the pyramid was built and was unfinished. The so-called^[2] Queen's Chamber and King's Chamber are higher up within the pyramid structure. The Great Pyramid of Giza is the only pyramid in Egypt known to contain both ascending and descending passages. The main part of the Giza complex is a setting of buildings that included two mortuary temples in honor of Khufu (one close to the pyramid and one near the Nile), three smaller pyramids for Khufu's wives, an even smaller "satellite" pyramid, a raised causeway connecting the two temples, and small mastaba tombs surrounding the pyramid for nobles.

History and description

It is believed the pyramid was built as a tomb for fourth dynasty Egyptian pharaoh Khufu and constructed over a 14- to 20-year period.^{[clarification needed]} Khufu's vizier, Hemon, or Hemiunu, is believed by some to be the architect of the Great Pyramid. It is thought that, at construction, the Great Pyramid was originally 280 Egyptian cubits tall, 146.5 metres (480.6 ft) but with erosion and absence of its pyramidion, its present height is 138.8 metres (455.4 ft). Each base side was 440 royal cubits, 230.4 metres (755.9 ft) long. A royal cubit measures 0.524 metres.^[5] The mass of the pyramid is estimated at 5.9 million tonnes. The volume, including an internal hillock, is roughly 2,500,000 cubic metres. Based on these estimates, building this in 20 years would involve installing approximately 800 tonnes of stone every day. Similarly, since it consists of an estimated 2.3 million blocks, completing the building in 20 years would involve moving an average of more than 12 of the blocks into place each hour, day and night. The first precision measurements of the pyramid were done by Egyptologist Sir Flinders Petrie in 1880–82 and published as The Pyramids and Temples of Gizeh. Almost all reports are based on his measurements. Many of the casing stones and inner chamber blocks of the Great Pyramid were fit together with extremely high precision. Based on measurements taken on the north eastern casing stones, the mean opening of the joints is only 0.5 millimetres wide (1/50th of an inch).

The pyramid remained the tallest man-made structure in the world for over 3,800 years, unsurpassed until the 160-metre-tall spire of Lincoln Cathedral was completed c. 1300. The accuracy of the pyramid's workmanship is such that the four sides of the base have an average error of only 58 millimetres in length.^[10] The base is horizontal and flat to within 21 mm. The sides of the square base are closely aligned to the four cardinal compass points (within 4 minutes of arc) based on true north, not