Thanks for your question! The back wall was covered with a mosaic tile. Actually, if we had it to do over we would have mounted the wine racks into floor-and-ceiling mounted frames (also part of the Vintage View racking system) so that we didn't have to drill into the tiles (it was quite a bit of effort). We've also built cellars where the back wall was clad in rock and that was a very striking look. Lighting above and below the racking, gimbled so that it points back on the bottles is also a good look.