Relatively thin collectibles such as movie posters and sports jerseys, as well as relatively thin works of art and the like are displayed through transparent bottom wall regions of relatively thin protective enclosures that are sized the same as and substituted for selected ceiling tile in a suspended ceiling. Each of the protective enclosures has a top wall that overlies at least a transparent region of the enclosure's bottom wall. Preferably the protective enclosures are generally square or rectangular to correspond with the size and shape of the ceiling tile they replace, and have top and bottom walls that extend substantially the full widths and lengths of the enclosures for being connected near their perimeters to cooperate directly or with short upstanding side walls to define thin display compartments that are closed to minimize the circulation of ambient air therethrough for protectively housing collectibles that are to be displayed through transparent central regions of the bottom walls. Provision is made for the bottom and top walls of the enclosures to be separated when access is needed to the display compartments for display changes and cleaning.