The greatest discovery of all time is Posted on June 21, 2015June 21, 2010 by admin “The greatest discovery of all time is that a person can change his future by merely changing his attitude.” — Oprah Winfrey Author: Oprah Winfrey Category: great Tags: great, Oprah Winfrey Spread the love Related posts: My idea of heaven is a great Any great warrior is also a scholar, Unconditional war can no longer lead to The great thing in the world is