My grandparents' home had a staircase wall filled with artwork. (Not above the stairs as you're walking up; the triangular part under the stairs — is there a name for that?) I loved that the space was filled, that you could stand in one spot and absorb not only the art itself, but the placement and juxtaposition.
Bathrooms provide a similar sort of canvas because they are smaller rooms whose walls can more reasonably be filled up than those of other rooms. Here are five bathroom gallery walls that inspire.
Shown above, left to right: