Ah, I see the Armistice Day article mentions "Called Armistice Day in many countries, it was known as National Day in Poland (also a public holiday) called Polish Independence Day
." Indeed it was a holiday here (I saw Polish flags on display more prominently, which is unusual here, unlike the US where one seems to see national flags everywhere all the time) commemorating Polish statehood again after many years of having been partitioned by other countries.
For Poles it was a long weekend. A friend invited a couple dozen of us for a weekend boardgaming retreat at a mountain lodge from Saturday to Tuesday, which was quite nice!