i'm doing research for a novel i am writing and would like some accurate scientific answers. in the novel i have most of the setting places in a long abandoned city set on the coast of the ocean. the city sits within the mouth of a huge cavern opening, with some of the city deep within the cave. the time is set for over 500 years after the city had been abandoned and this is the first time humans have set foot in it since that time. i'd like to know what the city would look like from scientific facts. for example: i understand moss and algae would grow all over the place due to the city's location near the ocean. i also understand wood would be decayed and anything other than stone would be virtually gone. however, i do not how much moss and algae would grow, or if other plants(since a forest is nearby) would grow as well. with a few parts exposed to sunlight, would trees grow through buildings or structures? also, what would the human remains look like. would there be skeletons left since the area is so exposed to the elements, or would it mostly be dust? also, is there anything i don't know about and haven't mentioned that might happen in these circumstances? any information is much appreciated.