The Great Pyramid is one of the Seven w【小题1】 . It took 100 000 people over 20 years to complete it The Great pyramid was considered a u【小题2】 building in the 19^th century AD. All that time, it was still the tallest building in the world. According to scientific research, the ancient King, Khutfu, 【小题3】(命令) his men to build the Great Pyramid stone by stone. The biggest stone weighs as much as 15 tons, Each stone was fixed so well, t【小题4】 the ancient workers didn't have any modern tools. The Great Pyramid has four sides and each side is 230.4 meters long and 146.5 meters high At that time, there were no modern machines or equipment, so how did the ancient Egyptians build the Great Pyramid? To this day, it is still a 【小题5】(奥秘) But many scientists continue to study their methods, The completion of the Great Pyramid shows the wisdom and the achievements of ancient Egyptian working people