The First Bird's Nest

We know why birds build nests. We also know how, where and when. But we'll never know the origin of nest-building. History is silent on the avian pioneer that first thought, "This lack of protection is killing the little ones. I've had enough, gosh darn it all!"

Mysteries like this keep us from feeling too confident in our intellectual capacity. Some knowledge will always be out of reach. This promotes inquisitiveness, which in turn spurs inventions that make life on earth more comfortable and enjoyable. If we knew how birds got the idea to build nests for their babies -- or how an ancient caterpillar that was so unhappy with its self-image figured out how to become a chrysalis and then a butterfly -- there's no way we would have those little round robot vacuum cleaners. Etc.