Rule reminder
Three passive constructions with distinct meanings: (1) 'essere + pp' = resulting state or general passive; (2) 'venire + pp' = active process, habitual/repeated action; (3) 'andare + pp' = obligation, necessity, what must be done. Choosing the right one depends on whether you want to describe a STATE, an ACTION being performed, or a DUTY.
'The museum is open (= in the state of being open) on Sundays.' Which form is correct?