The pyramids of ancient Egypt were designed as monumental tombs for the pharaohs. Years before the first pyramids were built, pharaohs were buried in smaller tombs. Later, larger and grander structures were erected as burial places, until the first pyramid, the Step Pyramid, was completed in the 2600s BC. Later, perfect, smooth-sided pyramids were built. The last royal pyramid was built for Ahmose I (1550–1525 BC). The pyramids were built on the edge of the Western Desert, part of the Sahara Desert, just at the point where it slopes down to meet the lush lowlands of the Nile floodplain. Most were sited within a few kilometres of the royal capital, Memphis.

Mastabas

Grander burial places were needed for the first kings of Egypt. Called mastabas, these tombs were flat-roofed, rectangular structures with painted “niched” walls. Inside a mastaba there were chambers for storing burial goods and provisions, chapels and an underground burial chamber.

The Step Pyramid was built in stages, beginning with a simple square mastaba. Workers built a central core made of roughly-shaped stones with a fine limestone casing. Then they added sloping upright layers to the core, each layer leaning inwards. The stones they used were bigger and of better quality than in the core.

Below the Step Pyramid, the builders carved out a complicated network of shafts, tunnels, chambers, galleries and storerooms, totalling 5.7 kilometres (3.5 miles) in length. The great central shaft, 7 metres (23 feet) square, was dug 28 metres (92 feet) down into the bedrock. Below it lay the granite-walled burial chamber.

Sneferu's pyramids

Pharaoh Sneferu (2575–2551 BC) was the greatest of the pyramid-builders, responsible for the construction of three of them. He was the first to build smooth-sided pyramids. He also introduced the internal design in which a long descending passage ran from the entrance in the north face down to the burial chamber at ground level. Sneferu's first pyramid, at Meidum, was originally a step pyramid like Imhotep’s, and was built using the same construction method. But about 15 years into his reign, Sneferu decided to abandon it.

Perhaps dissatisfied with its imperfection, Sneferu ordered yet another pyramid to be constructed. With a gentler slope planned from the outset, the North or Red Pyramid was successfully completed without mishap.

In the last years of his rule, Sneferu returned to his first project at Meidum and commanded his workers to fill in the steps to make a smooth-sided pyramid, 92 metres (300 feet) high.