There is a famous story with Rav Chaim Kaniesky about how he never really knew what the "chagav" looked like - how to identify the kosher grasshopper described in the Torah. One time when he was learning the related gemara, suddenly a chagav showed up in his room. Rav Chaim inspected it, decided it met the criteria of the gemara and therefore is obviously the elusive chagav and the miraculous story of how the chagav appeared so Rav Chaim Kanievsky could understand the gemara that much better was retold.. I might have some the few details not 100% accurate, but that is the gist of the story of Rav Chaim Kanievsky's grasshopper miracle..

According to Kikar, Rav Chaim Kanievsky's apartment has been undergoing some renovations. According to the story, it seems unclear but it looks to me like this happened before the renovations began, Rav Chaim woke up from his sleep on a Friday night and looked at one of the walls. He told his family that he is worried that the wall, that wall was where the grasshopper miracle had occurred, would be knocked down.

And what's wrong with knocking down the wall?

Rav Chaim explained that a story had happened with the Chida that a miracle had happened on stairs near his house. A short while later the Chida wanted to cover the stairs with gold as a sign. Marking the place of the miracle in such a fashion would strengthen other Jews in their faith. Therefore, Rav Chaim said, it is very important that the wall upon which the grasshopper miracle had occurred should remain intact.

Interesting story.