what's behind

Many of us have kept childrens' natural curiosity for other peoples' dwellings. I remember my first visit to Amsterdam long time ago, walking along the canals and discovering - to my big surprise - that there are no curtains in the beautiful large windows, inviting passers by to peep in. I learned then that in the protestant cultures nobody has to hide anything, unless s/he wants to commit a sin (!). Leaving the "sinful" aside, to me there's always been something mysterious and unsettling about courtains (remember Blue Velvet?) Hence a collection of some images around the nagging question: what's going on behind?