The Torah (Dev 27: 4-8) commands that we write every word of the Torah in plastered stone on Mt. Ebal.
Why? And why on this mountain, of all places?
I would suggest that the placement is critical to answering the question: Mt. Ebal is one of the highest peaks in Israel, and it overlooks Shechem. And Shechem is the first place Avram came when he entered the land, and the first place Yaakov came to when he came back into Israel from the East. Shechem is in the valley between two mountains, and the main road to the East comes out of it. In other words, Shechem is a primary gateways to the land.
If someone were to enter the Land of Israel, they would come to Shechem, and be naturally curious about what sort of people live there. The presence of the complete text of the chumash on the mountaintop over the town, in stone, would have provided a complete answer for any interested party.
There is a corollary here. Shechem, in addition to all of its other history with the Jewish people, was also the very first place when someone who was not already a member of the tribe sought to join the Jewish people – Yaakov’s family. As we know, they failed, because both their motives and means were unacceptable.
The Torah on the mountain was complete, including the cautionary tale of Shechem: if someone wanted to become Jewish, there were some pretty clear lines that had to be respected, including respecting Jewish women.
I would add as a footnote that the reason why the Torah was to be plastered was partially because plastered stone would be more visible from a distance. But plaster also weathers away much faster than stone, and needs constant maintenance to remain in good condition. When the Jews carved the Torah in stone, the people would have to remain engaged in Torah on a regular basis just to keep the letters in good condition.