Traps

At some times in human history, land has been left in such a state that future generations of people (or animals) can safely inhabit it. This does not necessarily stop them from settling there--because they may not know of the dangers--and suffering some unpleasant results.

One example would be valleys downriver from mining complexes. Dangerous elements and chemicals (lead, arsenic, cyanide, mercury, etc.) leach into the rivers, soil, and water table. Those living nearby are, essentially, slowly poisoned.

Another example might be modern toxic waste dump sites or areas downwind from nuclear testing ranges. In such cases, dangerous chemicals again play a role, but they're joined by radiation and its long-term harmful effects.

Today, I thought that spiderwebs made a good parallel to such unhealthy areas. A spider builds a web and lives there for a time, doing spidery things. Then it leaves. Perhaps it dies; perhaps it just moves. From personal experience and from movie sets, I know that most spiders don't remove their webs before leaving. Bugs come along and get stuck in those webs, just as they would normally do, but now there is no spider around to do anything with them, to clean the web, to shove out the bugs it doesn't want to eat, and so on.

What I'm trying to say is that I should probably sweep up the abandoned spider webs that have built up around the front porch light.