Active and retired first responders, military members and valley residents will climb 2,071 stairs at Gila River Arena beginning at 8 a.m. The climb honors first responders who lost their lives at the World Trade Center on 9/11 and recognizes those who continue to protect us from foreign and domestic threats. There were 110 floors and 2,071 steps in each of the Twin Towers when the buildings collapsed. Photographs of fallen heroes will line the stairs. Proceeds benefit the 100 Club of Arizona and Arizona Fighter Country. Those unable to complete the stair climb and kids under age 12 are invited to participate in a 4 lap, 2,071 step concourse walk and roll. $35-$40.