Hachidairyuo Shrine is a sacred place where the spiritually minded come together to pray. You can do the same, or respectfully observe others as they worship.
Situated in Unzen, this sacred place is worth a look. But you'll find loads more to discover in this area. Unzen Jigoku Hell, Hara Castle Ruin, and Vidoro Museum aren't too far from Hachidairyuo Shrine.