Who destroyed the great pyramids of Giza?

Answer 1

The caliph al-Ma'moon [ruled 813 - 842] attempted to destroy the pyramids but failed. He did this because of the belief that you do not leave any image without defacing it or any built-up grave without levelling it. The fact that these were part of the legacy of mankind was looked upon as a flimsy excuse.

Answer 2

During the expansion of the Islamic empire, many of the ancient sites were destroyed as the Muslim invaders declared the structures to be idolistic. The leader of the invasion is known to be the Arab caliph Abdullah al-Mamun who entered the pyramid around AD 820.

Prior to the planned deconstruction of the pyramids of Giza, the Coptic Egyptians maintained the structures in decent order. Roman writings from prior to Islamic invasion of the empire describe the pyramids as having smooth limestone surfaces. The largest pyramid was white and the smaller pyramids were black and the other red.

The Islamic invaders attempted to destroy and disassemble the pyramids stone by stone but the task was too large of an endeavor so they halted the disassembly and buried the remaining structures. The vandalism of the Sphinx (nose) was also committed by the Islamic forces.

The Islamic Jihadist forces continue to this day to speak about and plan the continued disassembly of the largest structures ever built by ancient men and continued destruction of non-Muslim sites. In 2013, the Grand Mufti of Saudi Arabia, [top Islamic official] has declared that it is "necessary to destroy all the churches of the region."