The town where we lived before was infested with ants. I don't mean that there were a few ant hills here and there, I mean literally infested.
We found an ant mound outside of our rental that was larger than a hubcap.
My husband's office, which was tiled, had an ant mound developing...inside! On tile! How is that even possible?!
I'm not convinced that the town wasn't resting on top of a giant ant colony. Everyone had ant problems.
That place taught us a lot of things; namely, don't live in a town infested with ants. (Also, look for black mold before you move into a rental home, not after.) Our new place, though considerably smaller, is a gazillion times better than where we came from. However, I do still find a few pest problems at my job. It's like a constant reminder of where I came from and what to avoid in the future.
This bit of black stuff is not dirt on the sidewalk. It is also not mold growing on the concrete. That black spot is made up of hundreds of ants. No lie. If I had recorded it, you would see that it was wriggling and squirming...gross. I can't imagine how much money they are going to have to spend to make sure this mess doesn't end up inside a residence hall. I'm just glad this sort of thing isn't happening outside of my apartment.