is  Mount Everest (8,848 m (29,029 ft)) in the  Himalayas  of Asia. The highest known mountain in the  Solar System  is Olympus Mons  on the planet  Mars  at 21,171 m (69,459 ft). Definitions of "mountain" include: [ 2 ] Height over base of at least 2,500 m (8,202 ft). Height over base of 1,500 m (4,921 ft).–2,500 m