When I was a kid, my dad built me a treehouse. It was actually a house on posts situated between two big pine trees. I loved climbing up the steps and hanging out on the porch or playing "house" in the 8' by 8' space.
That treehouse has long been torn down at my parents' home. My husband and I live on three acres with about two of that covered in tress with paths cut through the woods and bordered by a creek. We've talked about building a treehouse, not just for our daughter, but for us: a small space with a porch overlooking the creek. It makes me sigh and feel relaxed just thinking about it.