Abstract: Construction modules made of concrete or other cementitious materials, as well as walls made from such modules, are shown and described. The modules bear internal passages through which cables, rods, or other elongated members may be extended. The members may then be tensioned to affix the modules together, and also to place the individual modules in compression and thereby enhance their strength. The tensioning members can be anchored to the members at opposing ends of a wall, and/or they may be affixed inside the passages within the members by flooding the passages with cement, grout, or other suitable adhesive materials. The modules may be formed with insulation, electrical boxes/wiring, furring strips, and other such features so that these features will be pre-installed when the modules are assembled into a wall.