I've just been reading Wikipedia's article on Beavers (the rodents before you lot get any other ideas). I didn't really appreciate how amazing they are before. Their dams and lodges are proper structures. I didn't know they build lodges, and they've learnt how to ventilate them. Also beavers are way larger than I thought. I imagined them being at most as big as a rat.
A photo of a beaver lodge from Wikimedia commons. The description is LLM generated from me asking Be My AI to describe the lodge specifically, and my wife confirmed that it's pretty accurate.