As it turns out, treehouses arenâ€™t just for kids anymore. Once upon a time, treehouses were small, tight spaces in which children could hang out away from their parents, out of their direct line of vision. Treehouses often served as a secret clubhouse of sorts, where battle of the sexes seemed most prominent â€“ most treehouses adorned with â€œNo Girls Allowedâ€ or â€œNo Boys Allowedâ€ signs. However, the Treehouse djuren isnâ€™t just for kids. It brings an updated, modern design to the table that will please even adults.