A module for mounting in a structure having an interior and configured for accommodating within this interior at least one person, the module comprising: (a) two transparent panes each having an inner surface facing towards the other pane and outer surface facing away from the other pane; (b) a sealing and spacing arrangement sealingly fixing the panes to each other along their periphery at spaced apart relationship, thereby forming between the inner surfaces of the panes a transparent sealed cavity with a sealing frame surrounding it; (c) an image producing device fixedly mounted within said cavity so as to allow viewing images produced thereby, from a viewing direction facing the outer surface of a first of said panes, while being spaced from the inner surface of the second pane; (d) at least one concealing component configured for preventing: ▪ said device from being viewed from a direction other than said viewing direction, and/or ▪ any proximate operational component associated with said device and located within said cavity so that, if not concealed, it will be viewed from a direction facing the outer surface of at least one of the panes, from being viewed in such direction, said device, said operational component, if any, and said concealing component being disposed so as to leave free for viewing through at least a portion of the cavity area; the module being configured for being mounted in said structure so as: ▪ to fulfill the function of a transparent member such as a window, a door or a wall, separating between the space in said interior of the structure accommodating said person and a region behind said member, and ▪ to allow viewing at least through said portion of the cavity. (a) two transparent panes each having an inner surface facing towards the other pane and outer surface facing away from the other pane; (b) a sealing and spacing arrangement sealingly fixing the panes to each other along their periphery at spaced apart relationship, thereby forming between the inner surfaces of the panes a transparent sealed cavity with a sealing frame surrounding it; (c) an image producing device fixedly mounted within said cavity so as to allow viewing images produced thereby, from a viewing direction facing the outer surface of a first of said panes, while being spaced from the inner surface of the second pane; (d) at least one concealing component configured for preventing: ▪ said device from being viewed from a direction other than said viewing direction, and/or ▪ any proximate operational component associated with said device and located within said cavity so that, if not concealed, it will be viewed from a direction facing the outer surface of at least one of the panes, from being viewed in such direction, said device, said operational component, if any, and said concealing component being disposed so as to leave free for viewing through at least a portion of the cavity area; the module being configured for being mounted in said structure so as: ▪ to fulfill the function of a transparent member such as a window, a door or a wall, separating between the space in said interior of the structure accommodating said person and a region behind said member, and ▪ to allow viewing at least through said portion of the cavity. ▪ said device from being viewed from a direction other than said viewing direction, and/or ▪ any proximate operational component associated with said device and located within said cavity so that, if not concealed, it will be viewed from a direction facing the outer surface of at least one of the panes, from being viewed in such direction, ▪ to fulfill the function of a transparent member such as a window, a door or a wall, separating between the space in said interior of the structure accommodating said person and a region behind said member, and ▪ to allow viewing at least through said portion of the cavity.