When I was a child you could enter any apartment building in my city. As many of them are very old, beautiful architectural elements like staircases or mosaic floors could be found there. Nowadays only the tenants have the key to the main door. So sometimes I sneak behind someone pretending to go for a visit and then, viola, I can photograph the treasures behind closed doors.
Staircase in Krakow, Poland. Staircase in Gliwice can be seen here.
Sonia en Route 