The steep slopes of the sunny side of the Valais were terraced centuries ago for agricultural land use. Therefore dry-stone walls were built-up, without cement or mortar, and then backfilled with soil. The less steep cultivation areas were better protected from sun and erosion and could be managed more efficient. The technique of drystone walls’ construction is superior to the modern techniques with concrete or mortar, both in terms of persistence as well as the quality of the soil environment. They also form ideal habitats for various plant and animal species such as the green lizard.