Nikola Tesla was the most intelligent man who ever lived, in my opinion. Einstein and he were neck and neck, because they shared something that few people acknowledge the power of today: Imagination. Did you know that Albert Einstein failed his college entrance exam 15 times, and could not do advanced mathematics? In fact, the mathematical parts of the Theory of Relativity were done by his wife. Einstein himself was considered a fool in scientific circles, because he could "barely do math."