In your opinion, what is the most powerful speech in history?

Despite not even being his most famous speech, I think that Martin Luther King's final speech "I've Have Been to the Mountaintop" is the most amazing example of public speaking ever.

The grand finale of Dr. King's great legacy. A speech given by a man who knew that his days were numbered. A speech given by a man who knew he would not live to see his dream come to fruition. Dr. King discusses the adversity that the Civil Rights movement had already faced and how these challenges were overcome through non violent methods. He challenges America and it's citizens to live up to the ideals of the country.

Somewhere I read of the freedom of assembly. Somewhere I read of the freedom of speech. Somewhere I read of the freedom of press. Somewhere I read that the greatness of America is the right to protest for rights. And so just as I said, we aren't going to let dogs or water hoses turn us around. We aren't going to let any injunction turn us around. We are going on.

The speech ends with Dr. King foreshadowing the possibility of his death, an event which would occur the very next day when MLK was assassinated at his motel in Memphis, Tennessee.

Well, I don't know what will happen now. We've got some difficult days ahead. But it really doesn't matter with me now, because I've been to the mountaintop. And I don't mind. Like anybody, I would like to live – a long life; longevity has its place. But I'm not concerned about that now. I just want to do God's will. And He's allowed me to go up to the mountain. And I've looked over. And I've seen the Promised Land. I may not get there with you. But I want you to know tonight, that we, as a people, will get to the Promised Land. So I'm happy, tonight. I'm not worried about anything. I'm not fearing any man. Mine eyes have seen the glory of the coming of the Lord.

So that's my vote. What do you view as the greatest speech in history and why?