When we moved into our little cottage which is appx. 120 years old, we were puzzled by the white framework that can be seen protruding from the wall. This was mirrored in the other corner of the same wall.
I eventually was brave enough to attack it to see what it was. At some stage, the alcoves on either side of the chimney breast had fitted wardrobes built into them and for some strange reason somebody had plaster boarded over them - just leaving the mouldings showing.
The wardrobes were approximately 2 feet deep and 5 feet wide, so this was a considerable amount of space that had just been boarded over. The wardrobe doors had been removed and the remaining structures were in pretty poor condition so we removed them completely and opened up the space.
I must admit that when I had my crowbar in hand to lever the plasterboard off I was anxious that I might find some hidden structural problem or something even worse!