The base measures approximately 230.3 meters on each side, with a slope of 51 degrees 50 minutes 40 seconds. The sides are oriented to the cardinal directions within a fraction of a degree -- an achievement likely accomplished by tracking stellar movements rather than using any magnetic instrument. Inside, three chambers occupy different levels. The lowest, cut into the bedrock beneath the pyramid, was left unfinished. Above it, the so-called Queen's Chamber sits within the masonry, its purpose still debated. Highest of all, the King's Chamber contains a granite sarcophagus and is roofed with massive granite beams, some weighing up to 80 tonnes, hauled from quarries more than 900 kilometers south in Aswan. Five relieving chambers stacked above the King's Chamber distribute the weight of the stone above, and it was in these sealed spaces that workers' graffiti preserving Khufu's name were discovered in 1837.

The attribution of the Great Pyramid to Khufu rests on converging lines of evidence that have only strengthened over time. In 1837, when previously inaccessible relieving chambers were opened, hieroglyphs in red paint covered the walls -- gang names that included the pharaoh's name, such as "The white crown of Khnum-Khufu is powerful." The surrounding cemeteries contain tombs of Khufu's family: his mother Hetepheres, his vizier Hemiunu (believed by many to be the pyramid's architect), and his wives and children. In 2013, the Diary of Merer was discovered at Wadi al-Jarf -- papyrus rolls written by a work-gang supervisor documenting limestone deliveries from Tura to "Akhet Khufu," the pyramid's ancient name, meaning "Horizon of Khufu." The diary names Ankhhaf, Khufu's half-brother and vizier, as the supervisor accepting stones at the construction site.

At completion, the pyramid was entirely sheathed in fine white limestone from the Tura quarries across the Nile, its surface smoothed to a high polish. Joints between casing stones averaged just half a millimeter wide. The effect must have been extraordinary: a geometric mountain of white stone reflecting and refracting sunlight across the desert. Over the centuries, that casing was stripped away -- mostly during the medieval period, when Cairo's mosques and palaces needed building stone. Today, only a few courses of casing stones survive at the base. Without its white skin, the pyramid lost about 8 meters of height from the peak alone, where roughly 1,000 tonnes of material are now missing. The underlying core structure, built of rougher local limestone with rubble filling the gaps, is what visitors see today. In 1874, Scottish astronomer David Gill installed a survey mast on the flattened summit; it has been replaced periodically due to erosion and remains there.

The ancient Greeks believed the pyramids were built by slaves, and that myth persisted for millennia. Archaeological evidence tells a different story. Workers' camps at Giza reveal a conscript labor force organized into crews of forty, subdivided into teams of ten, each with an overseer. Their graffiti show competitive team spirit -- gang names boasting of speed and strength. A construction management study in 1999, working with Egyptologist Mark Lehner, estimated an average workforce of about 13,200 people with peaks of roughly 40,000. In 2017, stonemason Franck Burgos conducted an experiment at an abandoned Khufu-era quarry, using replica copper chisels, wooden mallets, and ropes. When the stone was wetted, cutting speed increased sixfold. Burgos calculated that about 3,500 quarry workers could have produced the 250 blocks per day needed to finish the pyramid in 27 years -- well within Khufu's estimated reign.