Egyptian pyramids often took 10 years or more to complete. According to the Greek historian Herodotus, the Great Pyramid at Giza was built in 20 years by 100,000 workers and was meant to be a tomb for Pharaoh Khufu.
Inside the Pyramids, ancient Egyptians built a series of burial chambers, ventilation shafts and passageways. The Pharaoh's sarcophagus was placed in the king's burial chamber. The ancient Egyptians believed that a part of the Pharaoh's spirit remained with his body after death and so they buried with him anything that he might need in the afterlife including gold, favorite objects and pottery.
It is not definitively known why the ancient Egyptians stopped building pyramids. Well-known structural engineer and Egyptian construction specialist Peter James theorizes that the Egyptians quit building pyramids because they quickly began showing cracks and imperfections. James believes that these imperfections in the pyramids are caused by what the Egyptians thought were improvements in construction techniques.