The Pyramids enable you to access all Government civics (greatly increasing your early management options). They also increase their city's chances of generating a Great Engineer.
Having Police State and Representation unlocked is very useful in the early game, making war rush tactics and the building up of your first six cities (respectively) a lot easier. Pyramids is essential when running a specialist economy because it enables a transition to Representation (with its powerful bonus of +3 beakers per specialist) very early. Also, Universal Suffrage could be efficient for richer states as an alternative to Slavery without angering and killing your people.
Built by the fourth dynasty of Egyptian rulers, the Pyramids represent the pinnacle of ancient Egyptian cultural achievement. Constructed on the Giza plateau outside modern-day Cairo, these structures were burial tombs and monuments for the Pharaohs, and may have taken generations and tens of thousands of workers to complete. The Pyramids are the only one of the generally accepted man-made wonders of the ancient world that remains in existence today.