This small church in the village of Crngrob, 4km north of Škofja Loka, has one of the most treasured frescoes in Slovenia. Look for it on the outside wall under a 19th-century portico near the church entrance. Called Holy Sunday (Sveta Nedelja) and produced in 1460, the fresco explains in pictures what good Christians do on Sunday (pray, go to Mass, help the sick) and what they don’t do (gamble, drink or fight).
Note that the church is normally locked, so try to arrange a viewing in advance through the TIC. Even when locked, the Holy Sunday fresco is still viewable – although some of its detail is hard to discern. (There's a helpful replica inside the Loka Museum.)
It's a nice walk or cycle to reach Crngrob – the Path to Crngrob brochure from the TIC outlines the way.