Pyramid

A pyramid is a geometric shape formed by connecting a polygonal base and a point called the apex by triangular faces. When unspecified the base is usually assumed to be square. One of the platonic solids, the tetrahedron, is a triangular pyramid. The square and pentagonal pyramids can also be constructed with all faces regular, and so count among the Johnson solids. All pyramids are self-dual. The volume of a pyramid is A × h / 3, where A is the area of the base and h the height from the base to the apex.

---

Pyramid-shaped structures were built by many ancient societies. The most famous are those in Ancient Egypt, where huge pyramids built of stone were used as tombs for pharaohs. The Great Pyramid of Giza is one of the Seven Wonders of the World, and the only one of the seven to survive into modern times. The ancient Egyptians smoothed the faces of their pyramids, though some of the stones used for the purpose have fallen out over the centuries.

To the south of Egypt the Nubians also built pyramids. They built far more than the Egyptians, but they are much smaller. The Nubian pyramids were constucted at a much steeper angle than Egyptian ones and were not tombs, but monuments to dead kings. Pyraminds were built in Nubia up until the 300s A.D.

The Babylonians also built pyramids with visible steps, sometimes called step pyramids, while those of Mesopotamia are usually called ziggurats. The Biblical Tower of Babel is often believed to be a Babylonian ziggurat.

A number of Mesoamerican cultures also built pyramid-shaped structures. These were also usually stepped and were used as temples, often sites for human and animal sacrifices.

There are other pyramid-shaped ancient monuments found in Central America and parts of Asia.

---

Esotericists have attributed remarkable properties to the pyramid shape and remarkable histories to historical pyramid buildings. The Great Pyramid of Giza has attracted special interest.

The pyramid shape is alleged, among other things, to keep razor blades sharp and to prevent meat from decaying. Researchers adhering to strict scientific standards have not substantiated these claims.

---

Pyramid is a concept album by the Alan Parsons Project, released in 1978.

---

Pyramid is the name of a game show currently in syndication. Perhaps some sort of disambiguation page is needed should anyone ever add significant information on this topic.

---

The hierarchical structures of some organizations are sometimes described as pyramids.