Complex sentence: Alma, which took the title from Leadville, Colorado, held on to the number one spot until 2006 when Winter Park, Colorado, became the highest incorporated town due to its annexation of a ski area.
Split into simpler sentences: Alma, which took the title from Leadville, Colorado, held on to the number one spot until 2006. In 2006, Winter Park, Colorado, became the highest incorporated town due to its annexation of a ski area.