When I was deciding what to do with my new tank, I was thinking going for a natural-local look. Here in Duluth, MN, the Lake Superior shore has a ton of rounded stones; granite, slate, etc., including a bunch of rounded off concrete rubble. So I thought going to the shore and grabbing a few buckets of stones would be a unique look, but ultimately decided against it so I could go more plants, but the thought is still with me if I do another large tank.