The Pyramids of Egypt

General
 The Pyramids of Egypt, built at Giza during the 4th Dynasty (circa 2680-c. 2544 BC) are the oldest of the Seven Wonders and the only ones remaining intact today, astonishing!

    The Great Pyramid of Khufu (circa 2600 BC) was the greatest of the Egyptian pyramids, which served as burial places of the pharaohs, particularly during the Old Kingdom. Some lists included all of the pyramids and the Sphinx as well.

     The great pyramids of Giza were built around 2700-2500 BC as tombs for the pharaohs (rulers of ancient Egypt, who held the status of gods on earth). It was constructed of around 2.3 million stones and each of the stones weigh from 2 to 30 tons each, think of the poor workers, who constructed it!

     Except for parts of the Mausoleum and of the temple of Artemis, they are the only one of the seven wonders still standing, Amazing!

Of the seven wonders of the world only the pyramids of Egypt have survived in a form that resembles their original condition. The largest of the three, known as the Great Pyramid of Khufu, was made up of approximately 2.3 million blocks of stone each weighing an average of 2.5 tons.Located in Giza on the west bank of the Nile River, near Cairo, the pyramids remain one of the engineering marvels of all time. Image, with no engineers or architects at all, the pyramids were built!

     The granite slab that is the roof of Khufu's burial chamber weighs 50 tons in itself, What a heavy load!

 Khufu's pyramid stands about 450 feet (137 meters) high. It is also in almost complete form, despite being the World's oldest Wonder, but still we classify it in one of the Modern wonders

     These monumental pyramids are precisely oriented to the four cardinal points, that is, North, South, East and West. The Great Pyramids of Giza still have a strong impact on humanity. The impact is best summarized in this ancient, but popular Arab proverb: "Man fears Time, yet Time fears the Pyramid."

Construction

The great pyramid is believed to have been built over a period 20 years, hard to believe, but true!

 The site was first prepared, and blocks of stone were transported and placed. An outer casing, which disappeared over the years was then used to smooth the surface. Although it is not known how the blocks were put in place, several theories.

The Structure
 The Great Pyramid was 145.75 m (481 ft) high when it was built. Over the years, it lost 10 m (30 ft) off its top. It ranked as the tallest structure on Earth for more than 43 centuries, only to be surpassed in height in the nineteenth century AD. It is made composed of 2,300,000 blocks of stone, each averaging 2 1/2 tons in weight. Despite the makers' limited surveying tools no side is more than 8 inches different in length than another, and the whole structure is perfectly oriented to the points of the compass.

     Until the 19th century it was the tallest building in the world and, at the age of 4,500 years, it is the only one of the famous "Seven Wonders of the World" that still stands. It is the Great Pyramid of Khufu, at Giza, Egypt. It was covered with a casing of stones to smooth its surface (some of the casing can still be seen near the top of Khefre's pyramid). The sloping angle of its sides is 51 degrees and 51 minutes. Each side is carefully oriented with one of the cardinal points of the compass, that is, north, south, east, and west. The horizontal cross section of the pyramid is square at any level, with each side measuring 229 m (751 ft) in length. The maximum error between side lengths is astonishingly less than 0.1%, unbelievable.