الخميس، 22 أكتوبر 2009

Pyramids

. The Great Pyramid

The largest pyramid ever built, King Khufu’s, is often called the Great Pyramid. It lies in the desert west of Giza, accompanied by the pyramids of Khafre and Menkaure (Khufu’s son and grandson). The Great Pyramid was built during Khufu’s reign (2551 bc-2528 bc). Vandals and erosion have stripped away some of the Great Pyramid’s outer material, and some of its uppermost levels have been dismantled, but it still retains its sense of majesty.

. Construction

The base of the Great Pyramid forms a nearly perfect square, with only a 19-cm (about 7.5-in) difference between its longest and shortest sides, out of a total length of about 230 m (756 ft). This huge square is also almost exactly level. When newly completed, the Great Pyramid rose 146.7 m (481.4 ft)—nearly 50 stories high. The pyramid’s core probably includes a hill of unexcavated rubble, making it impossible to determine its exact number of blocks. Researchers estimate that 2.3 million blocks were used to build the Great Pyramid, with an average weight of about 2.5 metric tons per block. The largest block weighs as much as 15 metric tons.

The work of quarrying, moving, setting, and sculpting the huge amount of stone used to build the Great Pyramid was most likely accomplished by several thousand skilled workers. Thousands more unskilled laborers and supporting workers—bakers, carpenters, water carriers, and others—were also needed for the project, so that a total of as many as 35,000 men and women were involved in the project. Many archaeologists and engineers now believe that the pyramid builders were not slaves, as was previously thought, but paid laborers who took great pride in their task. Most were probably farmers, contracted to work for a limited period. Specialists, who were permanently employed by the king, filled the positions that required the most skill—architects, masons, metalworkers, and carpenters.

In building Khufu’s pyramid, the architects used techniques developed by earlier pyramid builders. They selected a site at Giza on a relatively flat area of bedrock—not sand—which provided a stable foundation. After carefully surveying the site and laying down the first level of stones, they constructed the Great Pyramid in horizontal levels, one on top of the other.

Most of the stone for the interior of the Great Pyramid was quarried immediately to the south of the construction site. The smooth exterior of the pyramid was made of a fine grade of white limestone that was quarried across the Nile. These exterior blocks had to be carefully cut, transported by river barge to Giza, and dragged up ramps to the construction site. Only a few exterior blocks remain in place at the bottom of the Great Pyramid. During the Middle Ages (5th century to 15th century) people took the rest away for building projects in the city of Cairo.

To ensure that the pyramid remained symmetrical, the exterior casing stones all had to be equal in height and width. Workers marked all the blocks to indicate the angle of the pyramid wall and trimmed the surfaces carefully so that the blocks fit together. During construction the outer surface of the stone was left unfinished; excess stone was removed later.

As the Great Pyramid rose, the workers built large ramps to drag their materials up the sides of the structure. The exact form of these ramps is not known, but scholars believe that they were probably built wrapping around the pyramid as they rose. These ramps were probably made of desert clay mixed with water and bonded with limestone debris left over from the construction work.

When the workers had completed the pyramid and installed the pyramidion, or cap stone, ramps still covered the surface of the pyramid. As the workers dismantled the ramps from the top down, they slowly exposed the pyramid’s stone surface, which stonemasons smoothed and polished. When the ramp was gone, the pyramid was displayed in its full majesty.

B. Interior

The interior of the Great Pyramid is complex, with a series of passages leading to several rooms. The most important room is the King’s Chamber, the room in which Khufu’s body was placed during his funeral. In this room the priests left items that Khufu, like all Egyptians, would need for the afterlife. Although the builders tried to block passages and doors when they left the pyramid after the king’s funeral, tomb robbers did eventually take everything of value.

The entrance to the Great Pyramid was set 17 m (55 ft) above ground level. It was intended to be used only once, during Khufu’s funeral, when special scaffolding was erected. Once the scaffolding was dismantled, the entrance’s height served as a security measure against tomb robbers. The entrance leads to the Descending Passage, which runs down through the pyramid into bedrock beneath the pyramid and levels out until it reaches the Subterranean Chamber. About 18 m (60 ft) from the pyramid entrance, before entering the bedrock, the Descending Passage intersects another corridor, called the Ascending Passage, now sealed with three large granite blocks.

The Ascending Passage runs upward for about 39 m (129 ft), until it levels out and enters the so-called Queen’s Chamber. Early Arab explorers of the Great Pyramid gave it this name in the mistaken belief that the queen was buried here. Instead, it most probably held a statue of the king that represented his ka, a form of his spirit. The walls of the unfinished Queen’s Chamber grow closer as they rise and meet at a single point at the ceiling. This form results from each level of stones in the walls projecting slightly outward from the level beneath it, an arrangement called corbeling.

Where the Ascending Passage levels off horizontally and runs toward the Queen’s Chamber, it also intersects with one end of the Grand Gallery, a large, corbeled passageway 47 m (153 ft) long and 8.5 m (28 ft) high. The Grand Gallery most probably held some of the large stones that were used to plug passages after the king’s funeral. In the western wall at the point where the Ascending Passage and the Grand Gallery meet, there is an opening to a tunnel that winds its way down through the core of the pyramid and the bedrock to meet the Descending Passage near the Subterranean Chamber. It probably provided air to the workers carving out the Subterranean Chamber.

At the upper end of the Grand Gallery, another level corridor runs south into the King’s Chamber, a simple, rectangular room faced entirely with red granite. All that remains in the room now is a granite sarcophagus in which King Khufu was buried, near the western wall. About 1 m (3 ft) above the floor, near the center of the northern and southern walls of the King’s Chamber, are openings to shafts that run upward through the pyramid to the exterior of the pyramid. The exact purpose of these shafts is not known. Similar shafts lead out from the Queen’s Chamber but are blocked after 65 m (213 ft) and never reach the exterior of the pyramid.


Seven Wonders of the World

Seven Wonders of the World, works of art and architecture regarded by ancient Greek and Roman observers as the most extraordinary structures of antiquity. Only one wonder of the seven, the pyramids of Egypt, still stands today.

Several lists of wonders were drawn up during antiquity. The list known today is sometimes ascribed to Antipater of Sidon, a writer of the 2nd century bc and author of a travel book. The wonders in this list were all located near the eastern coast of the Mediterranean Sea and, except for the pyramids, were built in the four centuries from about 600 bc. The Seven Wonders are most often listed in the order in which they were built.

The Pyramids of Egypt were built on the west bank of the Nile River at Giza during the 4th Dynasty (about 2575 to about 2467 bc). The oldest of the seven wonders, the pyramids are the only one remaining nearly intact today. Their white stone facing was later removed for use as building material in Cairo. The largest of the pyramids is that of King Khufu, which is sometimes known as the Great Pyramid. It covers an area of over 4.8 hectares (12 acres). According to the Greek historian Herodotus, ten years were required to prepare the site and 100,000 laborers worked thereafter for 20 years to complete the pyramid, which contains the king’s tomb. Some lists include only the Great Pyramid, rather than all the pyramids (see Pyramids).

The Hanging Gardens of Babylon, perhaps built by King Nebuchadnezzar II about 600 bc, were a mountainlike series of planted terraces. Ancient historians report that Babylon at that time was dazzling in the splendor of its palace and temple buildings, fortification walls, and paved processional ways. The Hanging Gardens consisted of several tiers of platform terraces built upon arches and extending to a great height. Accounts of their height range from about 24 m (80 ft) to a less reliable estimate of more than 90 m (300 ft). Trees and colorful plants and flowers grew on the terraces, irrigated with water brought up from the Euphrates River. Archaeologists have discovered remains of walls along the Euphrates that may have belonged to the Hanging Gardens

source: http://encarta.msn.com/encyclopedia_761568384/seven_wonders_of_the_world.html