It's possible you grew up in an apartment building where the walls had ears; in coming years, we may live in buildings where the walls have lungs.
German company Blucher Technologies has developed a material called Saratech Permasorb Wallpaper, which is embedded with thousands of tiny spherical absorbers, which are themselves filled with thousands of branching passages that resemble the interior of lungs. These open passages within the spheroids absorb and store pollutants, making this the first wallpaper that actually cleans the air. And the filtration process works from both sides, so the wallpaper will also suck chemical pollutants out of the walls, for those that live in older buildings.
via 3 rings