Traditionally, on "Karfreitag"/"Holy Saturday"/"Easter Eve"/"Black Saturday" well, this Saturday, today, the public outdoor swimming pool (that's lido in proper English) season starts.
Yes. Until tomorrow. And since some weeks.
(The German physician and botanist, who wrote about it, knew that already in 1682 when he wrote his doctoral thesis "De ovis paschalibus" ['About Easter Eggs'].)