This chapel was in almost total darkness save for the one window on the side (which didn't let in much light, anyway). I didn't even have any idea the dome was there until my husband came and told me that you could pay to have the lights put on (as some Japanese tourists had lit up the altar). So we paid, and what a magnificent dome it was. It's a pity visitors may not know to do this because it's certainly worth the small fee to light it up.