What did the Tatars do with the enormous library of Baghdad?

The Tatars carried the precious books –millions of valuable books- and, simply and foolishly, threw them in the Tigris!
They were supposed to transport this huge library to Karakorum, the Mongolian capital, to benefit from this precious knowledge, since they were still in the stage of civilizational childhood. However, the Tatars were a barbarous people who neither read, nor liked to learn. They only lived to fulfill their desires and pleasures.
Their goal in this world was just to ruin it!
The Tatars threw the efforts of the previous centuries into the Tigris, to the extent that the water of the river turned black because of the ink, and a Tatarian horseman was able to cross over the huge volumes from one bank to another!
This was not only an anti-Muslim, but also an anti-humane crime! Sadly, it recurs throughout history:
It was committed by the Christian Crusaders in Andalusia, as we have previously mentioned, for the first time in the library of Cordova; for the second time in the library of Granada when it fell, whereupon they burnt over one million books in a public square; and for so many other times also in Andalusia in the libraries of Toledo, Civella, Valencia, Zaragoza, and others.
It was also committed by Christian Crusaders in Shaam, in the library of Lebanese Tripoli, whereupon they burnt over 3 million books.
It was committed once again by the Christian Crusaders in Palestine, in the libraries of Gaza, Al-Quds and Ashkelon.

Then, it was committed by the new European colonizers who occupied the Islamic world in the 19th century. However, they were more intelligent; as they stole the books rather than burnt them. They took them to Europe; and the great libraries in Europe still contain a large set of the greatest compositions in different scientific fields on the surface of the earth, authored by Muslims throughout the centuries. There is no doubt that the authentic Islamic books in the libraries of Europe outnumber the important sources in the Islamic countries themselves.

The main concern of those invaders, throughout time, was to put a barrier between this Muslim Ummah and any field of knowledge, by means of burning, casting into the river or stealing their books, or even, in those days, changing their curricula to be void of their valuables. The invaders indeed know well the value of knowledge in the religion of Islam, and how the Muslims would be powerful if they could get it.
But, let us resume our talk about the Tatars and Baghdad.

Having finished ruining the library of Baghdad, the Tatars moved to the beautiful houses and splendid buildings, and destroyed and burnt them all, and stole their precious contents, and burnt what was not portable. They continued to do so until most of the houses of the city turned into heaps and ruins from which flames and smoke arose.
This painful situation continued for forty days, during which the streets of Baghdad were filled with piles of putrid dead bodies, and covered with the color of blood, and the city was overwhelmed by a horrifying silence. There were no voices other than the decadent laughter of the Tatars, or the weeping of women and children who had lost everything.

https://www.islamstory.com/en/artical/20762/tatars-library-baghdad