Season 15 of "American Ninja Warrior" returns with the most elite athletes in the country competing on the world's most difficult obstacle courses. Hosts Matt Iseman and Akbar Gbajabiamila, along with co-host Zuri Hall, are back to call the action as the ninjas make their way through the qualifying and semifinal rounds in Los Angeles before moving to the national finals in Las Vegas. With the biggest changes in show history, Season 15 will challenge the ninjas to race side-by-side and head-to-head across a high-stakes course with a spot in the national finals on the line. Additionally, the Mega Wall is even taller than before at 18½ feet and, for the first time ever, ninjas will need to complete all six obstacles in a designated time in order to earn a shot at the $10,000 prize. A top prize of $1 million will go to the winner who can conquer all four stages at the national finals.