A massive war between the Persians and the Byzantines weakens both empires. The Plague of Justinian wipes out millions. If not for these two events it would have been impossible for the Islamic conquest to spread beyond Arabia. This is the history the academe does not want you to hear. They spread the hagiographic version of Islamic history. This is the truth.
There has been a war going on for the past 1400 years for the destruction of Western civilisation. Plague had weakened the West, allowing Islam to spread, but because Islam never invented anything on its own, instead relying on knowledge stolen from conquered peoples, it stagnated. The Mongol invasions introduced new technologies to the West where lack of strong centralised authority and easy money allowed for great inovation. Hand cannons became guns, Indian mathematics became banking and mercantilism, and the desire to cut free of the Islamic yoke prompted explorers to find alternate routes for the acquisition of spices and, ultimately, the discover of the New World. The West surged technologically and beat back Islam until, by the 20th century, most of the Islamic world was divided up among Western colonies.
The West grew complacent, and Islam appropriated Western technology, growing stronger, waiting for the perfect opportunity to turn the tide of the war. March 1994, US President Clinton pulls out of Mogadishu. CIA trained Islamist Osama bin Laden saw this as the turning point in the war. The West had backed down. Furthermore, the West had grown soft. The elite intelligentsia had been denigrating the West for thirty years. The time was ripe to strike.
It's been twelve years since 9/11. Bin Laden and his ilk set out to destroy the Western way of life. With a United States government set on eliminating freedom of speech, the right to self defense, the total obliteration of privacy with unreasonable search and seizure of everyone's data, and the extrajudicial killing of Americans with drone strikes, it is safe to say that they have succeeded. The terrorists have won. The West is over.