I can't find anything on this subject anywhere in the Civilopedia. (Probably because I don't know what subject listing it would be under.) The Culture Report at the bottom of the panel says that there (were) 24 Archaeological Dig Sites, and 24 _Hidden_ ones. How do you discover a Hidden one? Walk an Archaeologist across the hex? Do they appear after all 24 of the unhidden ones have been excavated? Do they not appear until a given era commences, or a given tech has been researched? Why can't the subject be Searched (I tried) in the Civilopedia? Anyone _know_ the answers to any of these questions? I certainly don't.