the oldest man-made pyramid found is called the step pyramid. it is in the giza necropolis in saqqara, near cairo, egypt. it was built for king djoser thousands of years ago. later pyramids were built much larger. the largest one was the great pyramid of giza. it is near cairo. it was the tallest building in the world until the eiffel tower was built in paris, in 1889. the great pyramid was built by the pharaoh khufu (= cheops) from the ancient egyptian old kingdom. herodotus was told by his egyptian guides that it took twenty years for a force of 100,000 slaves to build the pyramid (with another ten years to build a stone causeway that connected to a temple in the valley below).