A system for making a liquid-retaining wall, and such a wall, such as a swimming pool wall, from prefabricated plane panels, the system comprising assembly means for assembling together two consecutive vertically-disposed panels, a low belt which supports the panels, and a high belt which is fitted to the panels, the assembly means holding together two assembled-together panels while allowing one of the panels to move angularly relative to the other about a vertical axis, and also including angle-determining means for ensuring that at least two consecutive panels are at a determined angular orientation relative to each other, and further including stiffening means for stiffening the assembled panels wherein each angle-determining means is constituted by a part presenting two arms that form a determined angle relative to each other.