The pyramids of Egypt fascinated travellers and conquerors in ancient times and continue to inspire wonder in the tourists, mathematicians, and archeologists who visit, explore, measure and describe them.

Tombs of early Egyptian kings were bench-shaped mounds called mastabas. Around 2780 B.C., King Djoser's architect, Imhotep, built the first pyramid by placing six mastabas, each smaller than the one beneath, in a stack to form a pyramid rising in steps. This Step Pyramid stands on the west bank of the Nile River at Sakkara near Memphis. Like later pyramids, it contains various rooms and passages, including the burial chamber of the king.

The transition from the Step Pyramid to a true, smooth-sided pyramid took placed during the reign of King Snefru, founder of the Fourth Dynasty (2680-2560 B.C.). At Medum, a step pyramid was built, then filled in with stone, and covered with a limestone casing. Nearby at Bahshur, construction was begun on a pyramid apparently planned to have smooth sides. About halfway up, however, the angle of incline decreases from over 51 degrees to about 43 degrees, and the sides rise less steeply, causing it to be known as the Bent Pyramid. The change in angle was probably made during construction to give the building more stability. Another great pyramid was built at Dahshur with its sides rising at an angle of somewhat over 43 degrees, resulting in a true, but squat looking pyramid.

The largest and most famous of all the pyramids, the Great Pyramid at Giza, was built by Snefru's son, Khufu, known also as Cheops, the later Greek form of his name. The pyramid's base covered over 13 acres and its sides rose at an angle of 51 degrees 52 minutes and were over 755 feet long. It originally stood over 481 feet high; today it is 450 feet high. Scientists estimate that its stone blocks average over two tons apiece, with the largest weighing as much as fifteen tons each. Two other major pyramids were built at Giza, for Khufu's son, King Khafre (Chephren), and a successor of Khafre, Menkaure (Mycerinus). Also located at Giza is the famous Sphinx, a massive statue of a lion with a human head, carved during the time of Khafre.

Pyramids did not stand alone but were part of a group of buildings which included temples, chapels, other tombs, and massive walls. Remnants of funerary boats have also been excavated; the best preserved is at Giza. On the walls of Fifth and Sixth Dynasty pyramids are inscriptions known as the Pyramid Texts, an important source of information about Egyptian religion. The scarcity of ancient records, however, makes it difficult to be sure of the uses of all the buildings in the pyramid complex or the exact burial procedures. It is thought that the king's body was brought by boat up the Nile to the pyramid site and probably mummified in the Valley Temple before being placed in the pyramid for burial.

There has been speculation about pyramid construction. Egyptians had copper tools such as chisels, drills, and saws that may have been used to cut the relatively soft stone. The hard granite, used for burial chamber walls and some of the exterior casing, would have posed a more difficult problem. Workmen may have used an abrasive powder, such as sand, with the drills and saws. Knowledge of astronomy was necessary to orient the pyramids to the cardinal points, and water-filled trenches probably were used to level the perimeter. A tomb painting of a colossal statue being moved shows how huge stone blocks were moved on sledges over ground first made slippery by liquid. The blocks were then brought up ramps to their positions in the pyramid. Finally, the outer layer of casing stones was finished from the top down and the ramps dismantled as the work was completed.

Most of the stone for the Giza pyramids was quarried on the Giza plateau itself. Some of the limestone casing was brought from Tura, across the Nile, and a few of the rooms were cased with granite from Aswan. Marks of the quarry workers are found on several of the stone blocks giving names of the work gangs such as "craftman-gang". Part-time crews of laborers probably supplemented the year-round masons and other skilled workers. The Greek historian Heroditus reported in the fifth century B.C. that his Egyptian guides told him 100,000 men were employed for three months a year for twenty years to build the Great Pyramid; modern estimates of the number of laborers tend to be much smaller.

Pyramid building was at its height from the Fourth through the Sixth Dynasties. Smaller pyramids continued to be built for more than one thousand years. Scores of them have been discovered, but the remains of others are probably still buried under the sand. As it became clear that the pyramids did not provide protection for the mummified bodies of the kings but were obvious targets for grave robbers, later kings were buried in hidden tombs cut into rock cliffs. Although the magnificent pyramids did not protect the bodies of the Egyptian kings who built them, the pyramids have served to keep the names and stories of those kings alive to this day.