I know I've read posts about this but can't for the life of me find them. I'm at a stall in the storyline while I wait for a large diamond to drop, so in the meantime I'm working on upgrading things that will eventually need to be fully upgraded. I know the library, tavern, jousting arena, one stable and one hatchery need to be. Those are done. I've also finished a cottage, conservatory, and the theater. I think I read the deep mine has to be level 5 (ugh)! What else?