I'm planning on visiting Warsaw, including a public holiday (Corpus Christi). I am planning on a morning mass in the old city and possibly joining the procession after that.
What leisure activities are available?
As far as I can tell, all museums are closed this day. My reading of the visiting hours at Royal Łazienki park is that the palaces will be closed, but the gardens will be accessible (and free of charge, because it's Thursday), so I'm guessing many locals will enjoy a picnic on that day. Is that correct, and what else is popular?