The pyramid is a
structure whose outer surfaces are roughly triangular and converge to a single
point at the top. The base of a pyramid can be trilateral, quadrilateral, or
any polygon shape, meaning that a pyramid has at least three triangular
surfaces (at least four faces including the base). The square pyramid, with
square base and four triangular outer surfaces, is a common version.
A pyramid's design, with the majority of the weight closer
to the ground, and with the pyramiding
on top means that less material higher up on the pyramid will be pushing down
from above. This distribution of weight allowed early civilizations to create
stable monumental structures.
Pyramids have been built by civilizations in many parts of
the world. For thousands of years, the largest structures on Earth were
pyramids—first the Red Pyramid in the Dashur Necropolis and then the Great
Pyramid of Khufu, both of Egypt, the latter the only one of the Seven Wonders
of the Ancient World still remaining. Khufu's Pyramid is built entirely of
limestone, and is considered an architectural masterpiece. It contains around 1,300,000
blocks ranging in weight from 2.5 tonnes (5,500 lb) to 15 tonnes (33,000 lb)
and is built on a square base with sides measuring about 230 m (755 ft),
covering 13 acres. Its four sides face the four cardinal points precisely and
it has an angle of 52 degrees. The original height of the Pyramid was 146.5 m
(488 ft), but today it is only 137 m (455 ft) high, the 9 m (33 ft) that is
missing is due to the theft of the fine quality limestone covering, or casing
stones to build houses and Mosques in Cairo. It is still the tallest pyramid.
The largest pyramid by volume is the Great Pyramid of Cholula, in the Mexican
state of Puebla.
