Valleys constitute the only really level landscapes in South Tyrol. They represent the rubble-filled drainage ditches of the mountains, and are relatively late geological formations. It was only with the withdrawal of the glaciers from the valley at the close of the last Ice Age (approx. 12,000 years ago) that enough rubble was made available in order to at least partially fill the deep incisions in the mountain sides. At steep slopes like at the "Ritten," the famous "earth pyramids" are formed.
Today, human activities are concentrated on the valley floors: Cities, villages, and intensive agriculture dominate the landscape.