Abstract: The improved sliding glass door or window includes several glass panels that are mounted free-floating in a split frame with an upper and lower section that permits the glass panels to form at least a portion of an external wall of a skybox or the like. The frame and the glass panels that form the portion of the external wall preserves the weatherproofing of the room while also maintaining the safety and security of the room. The glass panels include spaced apart stationary end panels and at least one movable intermediate panel and possibly more intermediate panels as desirable. The end panels each abut against respective room walls with a flexible strip to seal the sliding glass door or window to the walls. The movable intermediate panels may be moved interiorly toward a fixed wall to provide access to the exterior of the room. The intermediate panels seal against the stationary panels to seal the sliding glass door or window thereto.