Ladder of Divine Ascent

The 12th century Ladder of Divine Ascent icon (St. Catherine's Monastery, Sinai Peninsula, Egypt).

Via Wikipedia, where you may read much more about this icon, including what each rung of the ladder represents.

For me, I'm just fascinated by the imagery and surrounding elements ... demons pulling people off the ladder, the people on earth and in heaven all praying for those on the ladder. It is not only beautiful but makes us dig deeper, which is the point in the first place.