The Great Pyramid at Giza Cairo, Egypt

          Noted for being the only surviving member of the Seven Ancient Wonders of the World, the Great Pyramid is the largest of the 3 pyramids built in the ancient city of Giza, now part of greater Cairo, Egypt. The pyramid is believed to have been built around 2560 B.C. as a tomb for the Egyptian Pharaoh Khufu, and likely took 20 years to construct. (Egyptologists argue over man-power numbers, and estimates have ranged from 14,000 to 360,000 men). When built, the pyramid measured nearly 480 feet high, with the sides each measuring about 755 feet long. In addition, each side is oriented with one of the cardinal points (north, south, east and west). Nearly 2.3 million blocks of stone, each weighing approximately 2 tons, comprise the pyramid. The pyramid remained the world's tallest building for 4 millennia after it was built.