Built upon hills for defensive purposes, surrounded by thick defensive walls, steep embankments, or cliffs, these hilltop settlements provided natural defenses for their earliest inhabitants. In the Middle Ages, earthworks and stone and wooden palisades were typically replaced with massive stone and masonry walls, sturdy gates, and watch towers. In the late Middle Ages and Renaissance, even some of the smallest and most remote hill towns were adorned with churches housing works of art and impressive noble residences.