Gorgeously vintage 70s wallpaper, discovered under the nasty wood panelling in the back hall.
The ugly, greenish wood panelling in the back hall was starting to come off, and a quick look behind showed that there were wallpapered walls! We're tearing the panelling down now, then peeling the wallpaper (though it is so "vintage" that it's a bit of a shame), and then making it look like the back hall exists in the 2000s!
UPDATE: We're not going to tear down the wallpaper! We are likely going to wallpaper over it, but it will remain. :)