1 day. 100 miles. The idea sounds impossible to most of us, but that's the challenge Ashley Lindsey faces in 'Solstice,' which documents her attempt to finish the Western States 100 Mile Endurance Run in California's Sierra Nevada Mountains. The world's oldest and most prestigious 100 mile trail race, Western States runners travel from Squaw Valley to Auburn, battling bitter cold, stifling heat, and their own mental and physical limitations along the way. From mountain peaks to river canyons, runners climb over 18,000 vertical feet and descend nearly 23,000 feet on this ultimate challenge for long distance runners. 'Solstice' is the story of a rookie attempting to run 100 miles for the first time, and to prove that 'impossible' is just a word.

• Documentary