Flexi Says: Mt. McKinley, also known as Mt. Denali, in Alaska, is considered the tallest mountain on Earth when measured from its base to its peak. Mount Everest, however, can be considered the tallest mountain if measuring the highest peak above sea level. Its peak rises the highest above sea level at 29,029 feet (8,848 meters). Mt. McKinley has a peak that is actually the third tallest above sea level at 20,310 feet (6,190 meters). These differences in height above sea level vs. from the base to the peak are partly why you hear differences in which is considered the tallest mountain on Earth.
