Since 1979, Mountainfilm has been one of the longest-running and most successful film festivals in the United States. Maybe it's the awesome location in Telluride, Colorado, but we also think it's the subjects at hand: provocative environmental features, the best in adventure film, and thought-provoking cultural portraits on the human spirit. Outside Online went through 100 different films, from documentaries to shorts, and found 10 that you shouldn't miss.