Why do houses creak?

Sometimes I feel like cities are built on the backs of land turtles which are slowly walking around and we never realise, and our houses creak when the turtle stumbles, or like to a smaller extent where some of the houses are super old-fashioned caravans (basically houses built on giant molluscs that slide around) and so that someday in a hundred years the house you’re in now will actual move a couple of places down the street or something I don’t know I should stop thinking about this

fuck everyone this is what my house and it’s foundations look like.