Beavers have been working hard along the edge of the DesPlaines River. I used to think that the critters were doing a lot of damage to trees, but it turns out that the beaver is one of what is known as a "keystone species" because their work creates wetlands that are used by many other species. According to National Geographic, they're second only to humans in being able to manipulate and change their environment.
When I first came upon these, the trees reminded me a little of the sculptures on Easter Island.