Mount Everest rises 29,035 feet above sea-level making it the highest elevation above sea level; in other words, it has the greatest altitude.
IMAGE: By Rdevany (This is a digital photograph that I took) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons