The highlight of Rila Monastery is this magnificent church, built from 1834 to 1837, with distinctive black-and-white archways and three yellow-painted domes. Its exterior frescoes are richly coloured scenes of Bible parables, including some blood-curdling illustrations of the punishments awaiting sinners; look out for demons gobbling the damned whole, or lassoing sinners into hell. Some are autographed by Zahari Zograf, the most eminent of Rila's painters. Taking photos inside the church is prohibited (though this is loosely enforced).
Within the church, you'll find an elaborate wooden iconostasis created by master artisans from Samokov and Bansko, plus an enormous low-hanging chandelier decorated with ostrich eggs. Note the need for proper attire: men and women should cover up from collarbone to knee. Holy water is on sale within the church, for the bargain price of 1 lv per bottle.