I have a thing for volunteers that spring up from cracks. This summer I found a snapdragon blooming in the pavement when I was on a walk. I used to have Celosia that would grow in cracks along the driveway and the house.

Love this picture! Thank you!

Many thanks, Jennifer. The most unusual thing I've seen (in photos) is apple seedlings growing in cracks. In Kazakhstan, where apples are thought to have originated, there are entire forests of apple trees. They do so well there that they actually come up in cracks in city sidewalks.