The history of interactions among disparate peoples is what shaped the modern world through conquest, epidemics and genocide. Those collisions created reverberations that have still not died down after many centuries, and that are actively continuing in some of the world's most troubled areas.
I have been so very, very fortunate in my life. I've met or been in contact with several of my childhood heroes. I've interacted with people all over this planet, and even though I couldn't possibly hope to remember all their names, I remember a photograph, a poem, a sound, a joke, kind words of encouragement. All is not lost.