While I have heard of them, I don't know anything about them. I believe it is something you obtain before christmas and open a flap(s) each day leading to christmas. Under the flap is something religious, no idea what.
But we have received an advent calendar from overseas, a non christian country and it looks like a tourism promotion calendar. It shows castles, hot springs, temples, statues etc etc.
I look forward to tomorrow, the 1st and see what is under the first flap.