A treasure trove of facts for history lovers and trivia buffs! Each day, our fascinating this day in history calendar 2015 features an event in history that shifted the course of the world on that day, or a birth date of a great historical mover and shaker. An on this day in history calendar makes a great gift! Today in history calendar has an easel back. Each page a day calendar measures 6 1/8" wide x 5 1/8" high.