Through the doorway Tom had emerged from Brendan could see into a small living room with a wood floor and a bright-red sofa, a modern-looking, colorful abstract painting on the wall above it.

When his children knocked it off the wall with a wayward tennis ball 27 years ago, the family wrapped up the painting they knew as 'The Mike' and shoved it behind the sofa.

Berlin student bought a second-hand sofa bed at a flea market. Later on she learned she had been sitting on a baroque painting hidden inside the couch.