Out of the rolling sands of Egypt rise mysterious, conical forms: the pyramids. Across Egypt, there are 80 of various sizes. But it's the greatest of the pyramids, and the mightiest of the Great Pyramids, the Pyramid of Khufu, which ranks among the seven wonders.
The Greek called Khufu Cheops in their accounts. It stands alongside Giza's other two Great Pyramids: Menkaure and Khafre. Nearby, the Sphinx watches guard. Khufu's staggering height of 754 feet (230 meters) held reign as the world's tallest structure until the Eiffel Tower surpassed it in 1889.
The Pyramid of Khufu is not only the oldest of the ancient wonders -- it's the only one still standing. Situated on the Giza Plateau, near the city of Cairo, it was built during King Khufu's reign from 2589 to 2566 B.C. The pyramid is made of more than 2,300,000 limestone and granite blocks and weighs approximately 6.5 million tons (5.89 million metric tons). Its sloping sides pay homage to the sun god, Ra, symbolizing his rays of light. These slopes rise at 51 degrees and have an area of 5.5 acres [source: Great Pyramid of Giza Research Association]. Each block fits tightly together -- less than a fiftieth of an inch separates them. Its four sides are situated at each of the cardinal directions, which proves how closely the ancient Egyptians were attuned to astronomy.
Khufu was originally covered with a limestone casing. It may be hard to visualize a smooth, glistening pyramid because we are familiar with its rough, weather-beaten appearance. In the 14th century, earthquakes struck Egypt, toppling temples and snapping bridges. Khufu's limestone casing was removed and repurposed for repairs. As a result, the pyramid was lowered in height by five percent, reduced to a still-mighty height of 745 feet (227 meters) [source: History Channel].
Khufu's interior is no less impressive than its façade. Intended as a tomb for the king and his queen, its primary purpose seems to be housing their bodies and storing the goods they need for the afterlife. Compact shafts and dark passageways weave serpentine paths through chambers and dead-end at impassable tunnels and secret rooms. For centuries, pyramidologists, archaeologists who study pyramids, have been excavating Khufu. But their work has been challenging. Egyptians made Khufu almost impossible to navigate to deter thieves and protect the tombs and treasures within. Some rooms and chambers are sealed with slabs of stone. Other rooms seem to exist for no reason except as deterrents to would-be robbers. A room in the queen's chamber, for instance, contains nothing but sand. More empty chambers serve as relief chambers, absorbing the stress of the pyramid's weight [source: BBC]. Still others are simply undiscovered or impassable.
We don't know for sure how the pyramids were built. Most scholars agree that construction provided employment for peasants when the Nile River's annual flooding kept them from tending their farms.
They've always been a popular tourist destination, and Egyptians as well as ardent admirers of Khufu resent the pyramid's relegation to mere "runner-up" on the new list of world wonders.
Next, we'll learn about a wonder that may not have even existed: the Hanging Gardens of Babylon.