Basement remodeling, I need to know how to seal up limestone walls and ideas for the basement?

I recently bought a house built in the mid 1800s, in the basement it is all limestone: the walls, ceiling and stairs. I really want to keep the old look in the basement but I also live in Kansas and we have a lot of tornados so it needs to be safe. I just need to know how to seal it up and make it as strong as possible. Also the floors are dirt I was wondering if anyone had any ideas for the floors to go with the old look.

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