The Pyramids of Giza in Egypt consist of three main pyramids and several smaller ones. The three pyramids are (in order of size) the Great Pyramid of Khufu, the Pyramid of Khafre, and the Pyramid of Menkaure. They consist one of the most important landmarks in Egypt.
The largest of the pyramids, the Pyramid of Khufu, was built in honor of King Khufu, the founder of the fourth dynasty of Egypt who reigned from 2589-2566BC. It is the only one of the Seven Wonders of the Ancient World still in existence. It is also known as Cheops in Greek. The pyramid stands 147 meters (481 feet) high. It is considered to be the second true pyramid ever built. The first being the Red Pyramid in Dahshur, Egypt.
The mathematical accuracy of the Great Pyramid of Khufu is stunning. It is aligned almost perfectly north. John Taylor is the one who first proposed that the number pi was first calculated to build the Great Pyramid of Khufu. If one divides the perimeter of the pyramid by its height, a very good approximation of 2*pi is obtained. Another interesting fact is that the length of the base of the pyramid is exactly 365.2422 cubits, where a cubit is an Ancient Egyptian metric system. A solar year contains exactly 365.2422454 days! Such accuracy was not matched in human history until the 20th century.
The engineering feat of building the pyramid is equally stunning. It is the largest pyramid ever built, incorporating 2.3 million stone blocks, each weighing 2.5 to 15 tons each. It is believed to have been built over a period of 20 years with 100,000 workers in 3 month shifts (according to the 5th century BC Greek historian Herodotus). Historians today calculate that it is more likely that a figure closer to 4,000 workers either working full-time or being rotated by others were used to build the pyramid. Modern archeological finds indicate that the people who built the pyramid were skilled paid workers, as opposed to slaves. These would have included project managers, engineers, and labor workers. Moreover, carvings found at the pyramid portray the workers expressing delight having participated in this national project.
The pyramid`s interior is also impressive. The pyramid houses three burial chambers, with granite slabs weighing up to 80 metric tons. The first is underground, carved into bedrock. The second, above ground chamber was called queen`s chamber. We know now it was never intended to house one of Khufu`s wives but perhaps a sacred statue of the king himself. The third is the king`s chamber, which held a red granite sarcophagus placed almost exactly in the center of the pyramid.
The second largest pyramid in Giza is the Pyramid of Khafre. Although it is shorter than the Pyramid of Khufu, standing at 144 meters (471 feet) high, it appears taller since it was built on a higher platform. What the Pyramid of Khafre lacks in size, it makes up in beauty of sculptures surrounding it. The Pyramid of Khafre is well distinguished physically by the limestone that still covers its top. It was built for the third ruler of the 4th dynasty, King Khafre, in 2520BC. This pyramid is distinguished by the large entrance hall, colonnaded courtyard, niches for royal statuary, storage chambers, and interior sanctuary. The pyramid is also surrounded by large statues, including the Sphinx, which was carved out of bedrock and is considered to be the largest statue of the Ancient World.
The last pyramid of the Giza plateau, the Pyramid of Menkaure, stands at 65 meters (213 feet) and was built in 2490 BC. It measures at one-tenth the size of Khafre`s pyramid. Menkaure`s pyramid was sheathed in red granite, instead of limestone as the other two great Pyramids of Giza. Red granite was considered to be longer lasting and more expensive than granite. One interesting fact is that a sarcophagus in Menkaure`s burial chamber was found and shipped to England; however, the ship carrying the sarcophagus sank in the Mediterranean Sea.