High up in the Himalayas, everything is bleak. And you will die unless you descend. Quickly. This is the case on most really tall and really cold mountains. Death is constantly a threat.
But the deadliest mountains on Earth aren't necessarily the ones that cause the most deaths. Mont Blanc, for instance, is a relatively pedestrian Alp that nets 100 deaths a year, but that's because a climber doesn't have to be experienced to attempt it—loads of people head on up there each year.
The real way to measure a mountain's deadliness is to divide the number of ascents by the number of fatalities. We used 2008 data for all the 8,000-meter (called: eight-thousand-ers) climbs—the classic criteria for the super-tall mountains. Why? The nickname for that 8,000+ meter is the "Death Zone." Well then. (Mount Everest, it may surprise you, is not at the top. Neither is K2.)