Dry stone masonry walls are the most sustainable and maintenance-free structures on Earth. The craft of dry stone masonry has been alive for as long as humanity and has remained virtually unchanged for thousands of years. The term dry stone refers to a stone building process which uses no mortar or concrete to bind stones together. Instead, these super-durable structures remain extremely stable because all stones fit carefully to overlap each other. The longest dimension of each rock is placed lengthwise into the core of the wall, locking the structure
together using 
friction and gravity. Large cap stones anchor smaller stones beneath to finish the top of the wall. Water and drainage are never a problem with dry stone walls. This mortar-less construction method leaves no water trapped within the wall. Instead, the wall naturally percolates the water through itself which helps keep the stones dry and intact.

Dry stonework an be considered an option to concrete block systems because they are very comparable in cost and will last longer. Pressed blocks not only have a shorter life-span but also lack visual appeal and character of a natural stone wall. The stones used for dry stone walls are gathered at local quarries and delivered in bulk. This process does not deplete natural resources and does not involve massive amounts of fuel. Dry stone walls can be seen as a cost-effective, and green alternative to concrete block walls.