Ancient Egypt's remnants feature monuments, tombs and temples that continue to fascinate and intrigue historians and tourists alike. The Great Pyramid of Giza, aka the Pyramid of Khufu, is no exception. Its Grand Gallery was an engineering marvel that proved difficult to access -- but the effort was rewarding.
Khufu's pyramid was meticulously designed, engineered and built over about 20 years. Upon completion, it was the tallest man-made structure on Earth at 481 feet. The entrance and Great Gallery were hidden for centuries. The limestone casing was so precise and the stones fit together so seamlessly that the building was practically impregnable.
In 820, Abdullah Al Mamoun tried boring into the pyramid, but the rock was too hard. So he lit fires and then poured vinegar over the stones to cool them before battering through the weakened wall. Eventually he and his men located the upper and lower passageways and found the original entrance -- 56 feet from ground level -- sealed and intact. From the entrance, a narrow 93-foot passageway leads to an ascending passage that arrives at the Grand Gallery. The base is nearly 7 feet wide, while the top of the Gallery measures just more than 3 feet.
At the upper end of the Gallery is a shorter tunnel that leads to one of the relieving chambers above the King's Chamber -- another gabled structure designed to evenly distribute the massive weight of the stones above. Visitors can also see 54 slots carved into the walls of the gallery -- 27 on each side. It's not known for certain what purpose they had, but some experts believe they were used to help store and secure blocking stones during the pyramid's construction.
The walls of the Grand Gallery are distinguished by a corbelled arch of seven steps. The arch was made by setting the stones into the wall and projecting them toward the center of the arch from each side; the gap becomes smaller with each level until they meet at the top. This helps support the superstructure above, distributing its weight more evenly -- in this case, millions of tons of stone. It also creates a stunning visual and architectural feat when viewed from the bottom level.
