Disclosed are various embodiments of glass structures and the assembly of the same by way of laser welding. In one embodiment, the glass structures may comprise a lightweight mirror or other structure. In constructing a lightweight mirror, a core is assembled by creating laser welded joints between individual ones of a plurality of glass parts. At least one laser access opening is cut out in one or more of the glass parts or plates. In the assembling, various pairs of glass parts are positioned to create abutments therebetween. Further, a laser is directed through at least one laser access opening toward at least one of the abutments to create one or more of the laser welded joints.