An all glass composite building panel suitable for use as an integral structural member in roofs, ceilings, walls, and floors. The panel is constructed of three layers of glass separated by integral raised walls fused to the adjacent glass layers to define three possible combinations of two enclosed spaces; two layers of contiguous individual vacuum cells; one layer of contiguous individual vacuum cells and one layer comprising a serpentine passageway for liquid flow therethrough, said serpentine passage containing a heat absorptive material; or two layers comprising individual serpentine passageways for liquid flow.