The origins of the Advent calendar come from German Lutherans who, at least as early as the beginning of the 19th century, would count down the 24 days of Advent physically.
This Hunfeld, Germany City Hall building is turned into an Advent Calendar.
These are the traditional Advent Calendars that are filled with fine German Chocolates that I grew up with...well, there were four children in our family, so we took turns opening the doors. I have three children and every year we purchase a calendar from our Military Commissary for each of our children (the Commissary is like a grocery store, and because we have such a diverse community in the Army they provide many favorites from worldwide locations.)
Tonight I am working on cutting out this Advent Calendar with my Cricut.