DNJ, strife did not begin and probably will not end in our generation. I have attached a simple link to attest to the fact that from the very beginning of time/the world people have been fighting wars - very brutal wars at that where people were killed, enslaved, and women were raped. Most of these wars have been triggered or driven by religion and turf wars, mostly a combination of both. The days of old were no heaven on earth. Difference is that now we can watch the conflict and the results from afar and pray that they stay just there.

Our ancestors will smile if they could see this statement of yours, "Before now, the earth was clean and a wonderful place in our Solar System to live."...unless you are talking about the environment only.