The Tallest Mountain in the Solar System

Olympus mons on mars is the tallest mountain in our solar system. It rises 16 miles, that's over 84 thousand feet, or 25 kilometers above the surface of the red planet. Scientists hypothesise it grew so tall due to three different factors. The pole of gravity on mars is only about 38 % as strong as it is on earth. Actress viola davis explains why she wrote her latest memoir.