What would you say if you could say anything to the people of the past (before 1960s) who are now dead?

I think a lot about something like the following hypothetical scenario:<br>- If you had a chance to speak to people from the past in a way that you would be believed without the other person becoming spooked/freaked out, what message would you convey to people from the past?<br>- It would be interesting to see what kind of topics you would suggest be conveyed to people from the past, and what era of history you would be interested in talking to.<br><br>For example, I think it's incredibly important to talk to people from the past about things like the importance of preserving the environment, or the logical fallacies of racism and sexism (or at least, the negative consequences of them), the importance of women's rights, why the logical extreme of capitalism is perhaps not the best economic system (or at least, negative possible consequences of it), the importance of preserving the wilderness and forests, why the white man's burden is not what people should be doing, etc, etc.<br><br>The reason why I said "before 1960s" is that by the 1960s, for most of what I would want to say to the people of the past, I would already have a voice of people from the past who were themselves saying what I would like to say. <br>(By the 1960s, there were a lot of people talking about the importance of preserving the environment for example.)<br><br>However, I think that perhaps, for the time period of before the 1960s, it would be better for the message to be delivered by someone from the future... rather than delivered by someone from the past.<br>I think that if Martin Luther King Jr. delivered his message of logical fallacies of racism to people from ancient Greece, ancient Rome, or even the 18th century for example, the message might be more easily dismissed, because it would be delivered by someone who the past could more easily dismiss the message from. <br><br>Something like:<br>"Oh, white man's burden? That's just what the Romans did when they conquered everyone. Why would we listen to the opinions of some weird religious leader from another continent?"<br>"Oh, preservation of the wilderness? That's just what some hippie from another continent is saying. Why would we listen to that hippie when we the English know how to run an empire?"<br><br>This is a topic I have been thinking about more and more for a while now, and would be interested to hear what others in the sub think. <br>- What would you say?<br>- How would you convey that message to people from the past in a way that they would believe you (and that you wouldn't come across as insane or something negative)?<br>- What era of history would you be most interested in talking to, and why?<br><br>DISCLAIMER: Obviously this is a hypothetical scenario, and in reality, time travel is very unlikely to be possible. However, if possible, what would you say?