Abstract: Novel, plastic interlocking wall panels, having a high strength to weight ratio, are disclosed which are employed in a reinforced wall construction especially adapted for use in swimming pools. The wall panels and reinforced wall construction are characterized by their ability to be assembled in a strong, rigid unit without the necessity of employing bolts, fasteners or welding. Particularly, the construction in the most preferred embodiments employs structural elements prepared by the extrusion of plastic materials, and more particularly, plastic materials which have a cellular core of reduced density as a characteristic feature.