While the rest of the world celebrates Halloween, Lutherans and most other Protestants celebrate Reformation. On this date in 1517, Martin Luther nailed his 95 Theses, a call for a debate on the Catholic practice of selling indulgences for sins, on the door of the Castle Church in Wittenberg as well as other items of Catholic dogma, to the door of the Castle Church in Wittenberg, Saxony (modern-day Germany).