The Middle East is the birthplace of civilization and with that comes millennia of accomplishments.
To me, the history of Arab-Islamic world is a disturbing example of quick and great success ended with seemingly unexplained stagnation and decline. If I was an alien visited Earth sometiome between 800 and 1400 AD, I'd came to conclusion that future belongs to Islamic world: huge cities, widespread literacy, trade, rational science (here is my favorite person), common spoken language and inclusive ideology. By "inclusive" I mean that neighbors of this civilization were expected to convert to Islam to be accepted as equals. Maybe this picture is a bit idealized, but the fact remains: they were for centuries ahead of Christian Europe and, as it seemed, all doors to further success were open...
And yet, this promising civilization failed. Why did this happen? We must know for sure, at least to not repeat the same mistake.
Except we do know exactly why this civilization failed. It was the medieval equivalent of a nuclear war: the Mongols.
The Mongol sacking of Baghdad was so complete, the nation didn't recover. Period. And Iran didn't recover their population until around the 1900s. Baghdad was the center of the Arab/Islamic world up until the Mongols destroyed it. Then the center became Cairo in Egypt, but Egypt hadn't been a relevant world power for almost two thousand years by that point. The Ottomans hadn't formed their empire yet; the Byzantine empire still existed at this point.
What's more, the Mongols destroyed Song Dynasty China. This is extremely important because the Southern Song Dynasty was very close to an industrial revolution. So close: they had joint-stock companies, they were refining steel, mining coal, and drilling for oil. They even had a printing press centuries before Gutenberg. Then the Mongols utterly destroyed them, subjugated them for about 3 centuries, and subsequently retarded their development until communism arose in 1949, seven centuries later.
Russia was an example of a country that benefited since it was the Mongol threat that united Christendom around the Muscovite, but it was still extraordinarily bloody and savage. But Iraq, Afghanistan, Iran, Jordan, Syria, etc.? Might as well have been nuked.
This allowed Europe to leapfrog the Orient. The Ottomans and Egyptians were the last remnant of "Arabic civilization" for centuries. It happened far enough away in history for it to feel like ancient history but close enough for the effects to still be relevant.
Also, there's a strong argument to be made the Mongols introduce the Black Death to Europe. The Mongols killed about 10% of all humanity, and the Black Death further killed a quarter. This not including other killers like smallpox and the Little Ice Age. So between 1250 to 1400, 35% of all humans just died.
It's astounding we don't learn more about the Mongols in history books considering how totally they changed the course of history. Without the Mongols, the Middle East would have been par with Europe, China would have industrialized a thousand years ago, Africa would not have been exploited anywhere near as much until Chinese imperialism happens upon them, Europe would have remained balkanized (and likely would have been exploited just as much as Africa), the Americas would have been colonized by the Chinese, the world population would have reached a billion by 1700, and Christianity would not have been anywhere near as strong.