Lone tree on top of a drumlin. This is a feature formed by the action of a glacier. One theory says that a drumlin forms parallel to the movement of the glacier as rock and earth below the ice are piled up to form a hill. The steeper, blunt end of the hill (left) faces the advancing glacier, while the longer, more gently sloping end (right) faces away from the glacier. Other theories say that drumlins can be formed by glacial floodwaters. This drumlin is near Menzingen, Switzerland, and was formed by the Linth Glacier that advanced over this area in the last Ice Age some 10,000 years ago.