Completed the following sentence: The historical roof was heavily damaged during World War II. <unk> <unk> <unk> Serious problems in the roof were reported in the 1970s, and some of them were solved in the 1980s. Problems in the roof were reported in the 1970s, and some of them were solved in the 1980s. ️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️<unk>️ In 2015, in preparation for
Expo Milano 2015, facades, statues, and mosaics underwent detailed cleaning and repair, using a giant moving crane scaffolding system.<unk> Expo Milano 2015, the facades, statues, and mosaics underwent detailed cleaning and repair, using a giant moving crane scaffolding system.