 Tribal nations see the recent birth of a rare white bison in Yellowstone National Park as a blessing and a warning. A few hundred people gathered outside the park this week to honor the animal and call for action. Lakota Chief Avril Lookinghorse told the crowd the calf's bull fulfills a prophecy that goes back two millennia. We are at the crossroads. It's up to each and every one of you to make it happen.