An Advent Calendar or Adventskalender (in German) is a unique calendar used to count and celebrate the days in anticipation of Christmas. The tradition dates to the mid-19th century, when German Protestants made chalk marks on doors or lit candles to count the days leading up to Christmas. In former days it was a simple painted cardboard with 24 windows, or doors, to open. Behind each window was a Christmas-themed picture. Today, Adventskalenders can contain pieces of chocolate, small toys, and many other kinds of tiny special gifts.