The Giza Necropolis (أهرامات الجيزة) is an archaeological site on the Giza Plateau, on the outskirts of Cairo, Egypt. This complex of ancient monuments includes the three pyramid complexes known as the Great Pyramids, the massive sculpture known as the Great Sphinx, several cemeteries, a workers' village and an industrial complex. It is located some 9 km (5 mi) inland into the desert from the old town of Giza on the Nile, some 25 km (15 mi) southwest of Cairo city centre. The pyramids, which have always loomed large as emblems of ancient Egypt in the Western imagination, were popularised in Hellenistic times, when the Great Pyramid was listed by Antipater of Sidon as one of the Seven Wonders of the World. It is by far the oldest of the ancient Wonders and the only one still in existence.
The Pyramids of Giza consist of the Great Pyramid of Giza (known as the Great Pyramid and the Pyramid of Cheops or Khufu), the somewhat smaller Pyramid of Khafre (or Chephren) a few hundred meters to the south-west, and the relatively modest-sized Pyramid of Menkaure (or Mykerinos) a few hundred meters further south-west. The Great Sphinx lies on the east side of the complex. Current consensus among Egyptologists is that the head of the Great Sphinx is that of Khafre. Along with these major monuments are a number of smaller satellite edifices, known as "queens" pyramids, causeways and valley pyramids.
Most construction theories are based on the idea that the pyramids were built by moving huge stones from a quarry and dragging and lifting them into place. The disagreements center on the method by which the stones were conveyed and placed and how possible the method was. A recent though unpopular theory proposes that the building blocks were manufactured in-place from a kind of "limestone concrete"
In building the pyramids, the architects might have developed their techniques over time. They would select a site on a relatively flat area of bedrock—not sand—which provided a stable foundation. After carefully surveying the site and laying down the first level of stones, they constructed the pyramids in horizontal levels, one on top of the other.
For the Great Pyramid of Giza, most of the stone for the interior seems to have been quarried immediately to the south of the construction site. The smooth exterior of the pyramid was made of a fine grade of white limestone that was quarried across the Nile. These exterior blocks had to be carefully cut, transported by river barge to Giza, and dragged up ramps to the construction site. Only a few exterior blocks remain in place at the bottom of the Great Pyramid. During the Middle Ages (5th century to 15th century), people may have taken the rest away for building projects in the city of Cairo.
To ensure that the pyramid remained symmetrical, the exterior casing stones all had to be equal in height and width. Workers might have marked all the blocks to indicate the angle of the pyramid wall and trimmed the surfaces carefully so that the blocks fit together. During construction, the outer surface of the stone was smooth limestone; excess stone has eroded as time has passed.