When we think about engineers who are working today, they are usually working on something that benefits society. They might be designing a bridge, a consumer device, or a new vehicle. Not so with the Great Pyramid in Egypt. Even today, thousands of years after its construction, the Great Pyramid is one of the biggest, heaviest, tallest things human beings have ever built. Yet it functionally accomplishes nothing. Engineers did not jump out of bed one day ready to build the Great Pyramid. They built a few test pyramids over the course of a century. The Pyramid of Djoser is a classic step pyramid 200 feet tall. The Maidum pyramid is a classic step pyramid with several of the steps filled in to start making a smooth pyramidal form. The Bent pyramid started with one slope, and then the engineers realized that it would not work, so they changed the slope midway. The Red pyramid gets the shape right, but is 140 feet shorter than the Great Pyramid. Then engineers were ready to build the Great Pyramid. They cleared off the sand on a 13-acre (5.26 hectare) site to expose bedrock for the pyramid's foundation. They oriented the pyramid almost perfectly north. Then they laid the base layer of stones, measuring 756 feet (230 meters) square. The stones came from quarries along the Nile River. The engineers had to do something fascinating during construction. They had to visualize the chambers, hallways, and shafts that would exist in three dimensions in the body of the pyramid, and they had to build them layer by layer during the pyramid's construction. This is the same kind of methodology that an engineer with a 3D printer uses today. Eventually the pyramid rose to a pinnacle at 481 feet (146 meters). The world's most gigantic monument was complete. The Great Pyramid stands out as an engineering triumph. >The Great Pyramid of Giza, pictured, is the largest and oldest pyramid in the Ciza Necropolis.