Pyramids are structures with four sides that slope upwards to a point. The most famous pyramids were built in Egypt more than 4,500 years ago. The Egyptian pyramids were built as tombs for kings to hold treasure and gold. The Great Pyramid of Egypt was built for King Khufu in 2550 BCE. The Great Pyramid is located in Giza, Egypt. 100,000 workers built The Great Pyramid over 20 years. They built the pyramids by stacking 2.3 million blocks of stone 470 feet in the air. Each of these blocks weighed about 2.5 tons which equals 5000 pounds!