FEA simulation of the double load-bearing system (LBS) for Pisa Tower is provided. Cylindrical trunk (T-LBS) is surrounded by 6-stage column system (C-LBS) in the telescopic manner. T-LBS is found out as the main object to bear the tower’s weight. Trunk is rigid and low-stressed. CLBS is partially (about 44 % of mass) hanging on the trunk by pliable cornices. Slender C-LBS is ...