There are many different theories to how the Egyptians built their pyramids. One of these is the Egyptian Theory, and another is the Alien Theory. Which one you believe is up to you.
A pyramid is a special type of polyhedron in which all the faces except possibly the base are triangles that meet in a common point called the vertex. Although they range in different heights, most of them are around 450 feet tall. They cover about the area of ten football fields. They are almost perfect vertically. In a common office building if the walls are off by three inches, that is considered excellent, and over time if the building sinks less than five inches that is also exceptable. These pyramids are less than half an inch off, and despite their weight, have only sunk about an inch in the many many years they have been here. Imotep, a architect and statesman, built thefirst known pyramid for King Zoser about 2650 B.C. It stands at Memphis, near Saqqarah. Thiry-five pyramids still stand near the Nile River in Egypt.