Yes, there are restricted areas in Milan Cathedral. The Duomo di Milano (Milan Cathedral) is one of the largest churches in the world and has a number of restricted access areas due to its size and history. Visitors can explore the main part of the cathedral but are not allowed to enter certain parts like sacristies, chapels, crypts or any other area that is considered sacred or private. These areas are marked with signs for visitors so they know what areas are off-limits. Photography may be prohibited in certain parts as well.