I have owned an apt in an older building for the past 10 years. Currently the unit is vacant as I have moved abroad. When I went back for a short visit I stayed in my apt and noticed that in the living area there is a large gapping crack that is the length of my living room and is not crawling down my wall. I have contacted the unit above me to see if they had recently done renovations etc... and they answered no. Has anyone ever experienced this or know what may cause this to happen?