Dotting the typical Maltese rural landscape is the Rubble wall (Ħajt tas-sejjieħ). This wall has been featured in the Maltese Islands since the time of the Arab rule (870-1127 AD), who established several new agricultural practices, irrigation methods and even crops.
Patience and craftsmanship are the two components required for the construction of these works of art. Even the use of tools is minimal – just a small axe (imterqa), spade and a string (lenza) to mark the limits of the wall. Stones of irregularly shaped sizes are placed one by one next to each other and layered, without the use of mud or concrete or any form of mortar. The structure is based on double external walls, filled with rubble (mazkan) in the middle.
Rubble walls serve many intrinsic purposes. They have been used as borders dividing fields for generations, but the most important role of these walls is ultimately environmental-related. In fact, these walls serve to filter and stop the soil from run-off and erosion. Cracks and crevices within the wall allow water to pass through, thereby preventing waterlogging. The soil is trapped and is prevented from being carried away from the field. Retaining rubble walls are often considered as a major local method to control soil erosion. Rubble walls also act as a refuge for different fauna species, e.g. lizards, geckos, butterflies and even host many different flora species. These include snapdragon, wild caper, spiny asparagus and the Sweet alyssum. The conservation and maintenance of all rubble walls and rural structures has been required by law through a legal notice since 1997 because of their historical and environmental importance.