<prompt> Andika a continuation for this paragraph - The historical roof was heavily damaged during World War II. Andika a continuation for this paragraph - The historical roof was heavily damaged during World War II. Kabla ya hapo, paa hilo lilikuwa limefanyiwa kazi nyingi za kurekebisha. Matatizo makubwa ya paa yaliripotiwa katika miaka ya 1970, na baadhi ya matatizo hayo yalitatuliwa katika miaka ya 1980. Paa tunaloona leo limepitia marekebisho mbalimbali ya kihistoria na linawakilisha masuala magumu ya kuhifadhi. Katika 2015, katika maandalizi ya Expo Milano 2015  <response>: , facades, sanamu, na mosaics underwent kusafisha kina na matengenezo, kwa kutumia giant kusonga crane scaffolding mfumo. 