The first dam was built in Egypt around 3000 BC by King Menes, known as the Memphis Dam. It was composed of cut stone masonry reaching 50 feet tall. The Great Pyramids of Giza, especially the Great Pyramid built for Khufu around 2550 BC, were engineering marvels that remained the tallest human-made structures for nearly 4,000 years. The Egyptians developed early forms of mathematics, timekeeping, locks, surgical sutures, and were the first to manufacture ropes, use cosmetics, and create paper and mints.