Building a pyramid was hard and dangerous. It took a very organized society to do it.
Thousands of skilled and unskilled workers were needed. We know the Great Pyramid at Giza is huge. But to build it, one giant stone block must have been quarried, shaped, and smoothed every two minutes for 23 years!
No one has ever found building plans that show how the pyramids were built. Modern experts have made some smart guesses. They based them on knowledge of modern construction.