I never met my great-grandparents. Pete has had the honor of knowing 4 of his. My mother's parents live close enough to us that we have been able to see them at least every few months. He has planted flowers and baked cakes and hiked and driven trains and played hide and seek with them. I am so thankful.
My grandmother, whose husband just died, has advanced Alzheimer's Disease. She is able to live at home, but has very little idea who we all are and needs 24 hour supervision. However, when Pete walks in the door of her house she lights up and walks directly to the place where the toys are kept. Watching them together reminds me why in many cultures several generations of a family live together in one home. Pete has adapted seamlessly and without question to her advancing Alzheimer's. He seems to understand that she has moved back into a "child" category and never turns to her for adult things (food/advice/permission).
So: Find the oldest and youngest people that you know. Add nature, a kitchen, a book, or a pile of toys. Mix. Stand back and be amazed. I am. Grandpa was.