Pyramids are monumental structures built of stone or brick with a rectangular base and four sloping sides meeting at an apex or truncated to form a platform, constructed at different times in Egypt, Sudan, the Mesoamerican region, and elsewhere. According to the Encyclopaedia Britannica’s architectural definition, they were raised for varied purposes and differ in form by culture, with the Egyptian and Central/South American traditions the best known Britannica. (britannica.com)

Origins and development in the Nile Valley

The earliest large stone pyramid known is the six‑tiered Step Pyramid commissioned by Djoser at Ṣaqqārah during Egypt’s Third Dynasty, designed by the high official Imhotep in the 26th century BCE; it rises to about 60–61 m within a vast walled mortuary complex and marks the translation of earlier mastaba forms into stone Britannica; Britannica. (britannica.com)

Under Snefru in the early Fourth Dynasty, builders experimented with true (flat‑sided) pyramids. At Dahshūr, the so‑called Bent Pyramid changes slope mid‑way (c. 52° to ~43.5°), while the Red Pyramid—about 104 m high—represents the earliest successfully completed true pyramid; at Meidum an earlier stepped core was filled to create continuous slopes Britannica; Britannica. (britannica.com)

Giza and the Old Kingdom apex

The Giza pyramid field includes the pyramids of Khufu, Khafre, and Menkaure, with the Great Pyramid of Khufu originally about 146.6–147 m high and ~230 m per side; it is precisely oriented to the cardinal points and built of millions of limestone blocks with granite in the burial chamber Britannica; Britannica. (britannica.com)

Giza’s pyramids formed parts of larger funerary complexes with valley temples, causeways, and subsidiary pyramids. UNESCO designates “Memphis and its Necropolis – the Pyramid Fields from Giza to Dahshūr,” noting the development from mastaba to pyramid and identifying more than three dozen pyramids within the property UNESCO. (whc.unesco.org)

Chronologically, Egypt’s “Old Kingdom” (about 2686–2181 BCE) frames the classic period of pyramid building, as outlined by major museum timelines British Museum. (britishmuseum.org)

Construction, materials, logistics, and labor

Ancient sources and modern archaeology indicate quarrying of local core limestone, transport of fine Tura limestone for casings and Aswan granite for internal elements, and raising blocks on ramps; casing stones once created smooth, gleaming faces Britannica; PBS NOVA; book://Mark Lehner|The Complete Pyramids|Thames & Hudson|1997. (britannica.com, pbs.org)

A 2024 geoscience study mapped a now‑abandoned Ahramat branch of the Nile, along which 31 pyramids from Lisht to Giza had causeways terminating at ancient riverbanks; the branch likely served as a waterway for ferrying building materials and personnel during the Old and Middle Kingdoms Communications Earth & Environment (journal://Communications Earth & Environment|The Egyptian pyramid chain was built along the now abandoned Ahramat Nile Branch|2024); National Geographic. (nationalgeographic.com)

Archaeological evidence also documents workers’ settlements and provisioning near the pyramid fields, supporting organized labor rather than enslaved mass workforces National Geographic book://Mark Lehner|The Complete Pyramids|Thames & Hudson|1997. (nationalgeographic.com)

Functions and associated texts

In Egypt, pyramids were royal tombs embedded in mortuary landscapes that included temples and processional causeways; the interiors of later Old Kingdom pyramids bear Pyramid Texts, reflecting funerary theology and royal afterlife rites Britannica; Britannica. (britannica.com)

Nubian pyramids in Kush

South of Egypt, the Kingdom of Kush developed a distinctive pyramid tradition with steep‑sided royal pyramids at sites such as Meroe; UNESCO identifies these cemeteries as the best‑preserved relics of Kush (8th century BCE–4th century CE) UNESCO. More than 200 pyramids are spread across the Meroitic cemeteries, forming the world’s largest single concentration of pyramids, as reported by field managers and surveys summarized by National Geographic National Geographic; UNESCO. (nationalgeographic.com, whc.unesco.org)

Pyramids in Mesoamerica

In central Mexico, the urban center of Teotihuacan was dominated by stepped pyramids used as temple platforms. The Pyramid of the Sun rises about 66 m with a base roughly 220 × 230 m; a cave and tunnel complex beneath was identified in the 1970s, and modern studies place its completion circa 200 CE Britannica; The Met, Heilbrunn Timeline. (britannica.com, metmuseum.org)

On the Yucatán Peninsula, the Chichen Itza complex includes El Castillo (Temple of Kukulkán), a stepped pyramid with four stairways of 91 steps each plus the top platform, totaling 365—an architectural manifestation of calendrical calculation; light‑and‑shadow effects resembling a serpent are visible near the equinoxes Britannica; UNESCO. (britannica.com, whc.unesco.org)

Mesoamerican temple‑pyramids were typically built of earth cores faced with stone and topped by shrines, differing functionally and formally from Egyptian tomb pyramids Britannica; Britannica. (britannica.com)

Distinction from Mesopotamian ziggurats

Although superficially similar, Mesopotamian ziggurats were solid, terraced platforms without internal chambers, ascended by exterior stairways or ramps and crowned by shrines; leading examples include Ur and Chogha Zanbil Britannica. (britannica.com)

Other world examples

In China, the Mausoleum of the First Qin Emperor at Xi’an is a vast funerary complex focused on a large earthen mound shaped like a truncated pyramid, begun in 246 BCE and surviving to a height of about 51 m within a double‑walled precinct, famous for its terracotta armies UNESCO. (whc.unesco.org)

Numbers and distribution

Scholars differ on how to count Egypt’s pyramids because of ruined, unfinished, and private examples, but estimates around 118–138 identified pyramids are commonly cited in specialist syntheses and reporting; by contrast, Sudan’s pyramid fields—especially around Meroe—collectively surpass Egypt in count though not in size Live Science; UNESCO; National Geographic. (livescience.com, whc.unesco.org, nationalgeographic.com)