My mother used to housesit for a women who decorated her house like this every year - putting so much detail and creating a full city underneath the tree. Many years ago, she was decorating her house and her husband said to her, "There's something different about it this year." "Oh, no, it's the same as every year!" she replied. "It's just... different" he said. The next morning, her husband died of heart failure. Ever since then, even when she has nobody coming for Christmas, she always decorates and puts the tree up herself, to memorialize the love of her life.