- This is about the polyhedron. For information on the pyramids of Egypt, see
Egyptian pyramids. For the games magazine, see Pyramid (magazine)
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  where A is the area of the base and h the height from the
base to the apex.
Structures
Pyramid-shaped structures were built by many ancient peoples. The most famous are the Egyptian pyramids – huge pyramids built of brick or stone, 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 with gold and
polished white limestone, though many 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
constructed at a much steeper angle than Egyptian ones and were not tombs, but monuments to dead kings. Pyramids were built in
Nubia up until the 300s AD.
The Mesopotamians also built pyramids called ziggurats, with a distinct series of layers. In ancient times these were brightly painted. Since they were
constructed of mud-brick, little remains of them. The biblical Tower of
Babel is believed to be a Babylonian ziggurat.
A number of Mesoamerican cultures also built pyramid-shaped structures.
These were also usually stepped, with temples on top, more similar to the Mesopotamian ziggurat than the Egyptian pyramid. The
largest pyramid by volume is that of Cholula, in the Mexican state of Puebla.
There are other pyramid-shaped ancient monuments found in Central
America and parts of Asia.
Pyramids were also found in Greece. One of these pyramids in Greece is older
than the pyramid of Cheops, as it was dated to 2720 B.C.
There is a pyramid in ancient Rome. The pyramid of Gaius Cestius was build by the end of the I century B.C., is 27 meters high
and still exists today, close to the Porta S. Paolo.
Modern pyramids
An example of a modern pyramid can be found in Paris, in front of the Louvre Museum.
The gymnasium for the baskeball and volleyball teams on the California State University,
Long Beach campus is a large 18-story-tall blue pyramid.
Esotericism
Esotericists have attributed remarkable properties ("pyramid power") to the pyramid shape and remarkable histories to historical
pyramids: pyramids are able to keep blades sharp and to prevent meat from decaying. Researchers adhering to strict scientific
standards have not substantiated these claims.
Related
Hierarchical structure
The hierarchical structures of some organizations are sometimes
described as pyramids. This often includes sports league
systems.
Game show
Pyramid is the name of a game show currently in syndication.
Novel
Pyramids is a Discworld novel by Terry Pratchett; see Pyramids
(Discworld).
Album
Pyramid is a concept album by the Alan Parsons
Project, released in 1978.
Magazine
Pyramid is an online magazine publishing role-playing and other game articles, published by Steve Jackson Games.
Confidence game
A pyramid scheme is a phony business, similar to a chain letter, that involves the exchange of money primarily for enrolling other
people into the scheme.
External links
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