The average velocity of international elite cross-country skiers has roughly doubled in the last 75 years! Male skiers now cover 50km in roughly 2 hours compared to 4hours back in 1920. In the shorter events, the improvement is not as great, but still 50% or more. Every aspect of XC skiing has changed; courses, equipment, technique, and the physical capacity of the skiers. Most of the really significant breakthroughs in skiing have occurred in the last 30 years. Here is a survey of the events that have helped skiers to keep pushing back the speed barriers, and a look into concerns for the future.