It is the oldest, and it is the only surviving of the Seven Ancient Wonders. At the city of Giza, and today part of Greater of Cairo, Egypt.
The monument was built by the Egyptian pharaoh Khufu of the Fourth Dynasty around the year 2560 BC to serve as a tomb when he dies. The great pyramid is believed to have been built over a 20 year period. .
The pyramid was first prepared, and blocks of stone were transported and placed. An outer casing was then used to smooth the surface. Although it is not known how the blocks were put in place, there are several theories. One theory involves the construction of a straight or spiral ramp that was raised as the construction proceeded. This ramp, coated with mud and water, eased the displacement of the blocks which were pushed into place. A second theory suggests that the blocks were placed using long levers with a short angled foot. .
The structure consists of approximately 2 million blocks of stone, each weighing more than two tons. It has been suggested that there are enough blocks in the three pyramids to build a 3 m (10 ft) high, 0.3 m (1 ft) thick wall around France.
On the north face, is the pyramid's entrance. A number of corridors, galleries, and escape shafts either lead to the King's burial chamber, or were intended to serve other functions. The King's chamber is located at the heart of the pyramid, only accessible through the Great Gallery and an ascending corridor. The King's passageway is made of red granite, as are the interior walls of the King's Chamber. Most impressive is the sharp-edged stone over the doorway. All of the interior stones fit so well, a card won't fit between them.
New theories concerning the origin and purpose of the Pyramids of Giza have been proposed, astronomic observatories, places of cult worship, geometric structures constructed by a long-gone civilization, extraterrestrial-related theories have been proposed with little evidence in support.
