To make a responsible bid for the summit of a mountain as extreme as Denali, climbers need to have years of climbing experience, have mastered a host of skills, and be physically and mentally prepared for the challenge. Denali is so massive that it creates its own weather. Storms blast climbers with hurricane-force winds and temperatures can sink to -40°F. The objective hazards on the mountain include crevasse fields, avalanches, and steep slopes. While the skills necessary to survive such weather and terrain cannot be practiced via the Internet, we have illustrated four that climbers must learn before tackling Denali. Click on any of the Survival Skills to find out more.—Thom Pollard