Lately I have been thinking of creating a world setting to write stories in. I want the timespan of the lore to be pretty big, covering from the time of ancient civilisations through to a modern state before moving on to dystopian and perhaps Utopian world state. What binds these disparate elements together is the existence of magic throughout the setting. Here, magic is something that occurs due to interdimensional rifts opening up in certain places of the world in certain time periods, and some of the people who are present in those places develop certain affinities to magic. Other fantasy elements such as monsters, enchanted places and such also occur as a result of this wonky interference. I want to do a sort of Highlander-esque take with the cast- the characters who have special abilities basically have natural immortality and their abilities become more pronounced and powerful gradually over time. I want such a timespan primarily because I want to try my hand at various genres while staying true to the core tenets of this premise. In such a context, would basing the world mostly on real-world locations and events be better, or would going for a more fictional take be better? I was already thinking of taking ques from various historical locations and civilisations such as Babylonian, Roman and such, but I am uncertain as to how this kind of real-world extrapolation can hold up in case I want to do something in the near (or far) future. Thoughts?