Since 2014, thousands of first responders, military members, and their families have attended the annual 9/11 Tower Challenge in Tucson to pay tribute to the nearly 3,000 lives lost on Sept. 11, 2001.
Participants climbed 2,071 steps at Arizona Stadium in past years, equivalent to the 110 stories in the World Trader Center's Twin Towers. This year, the Tower Challenge will be held at the Tucson Convention Center the morning of Sept. 11.
Registration for the event has ended. For more information on the annual tribute, visit https://www.facebook.com/911TowerChallengeFoundation.
Check out these photos from the Tower Challenges in recent years:
Photos: Thousands take the Tucson Tower Challenge in remembrance of 9/11 terrorist attacks
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Zachary Dietrich holds a flag as he makes his way up a set of stairs with the rest of Pima County Sheriff's Department recruit class 19-2 during the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Pascua Yaqui Firefighter-paramedic Dennis Rodriguezduring makes his way up a set of stairs during the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Pascua Yaqui Firefighter-paramedic Dennis Rodriguezduring makes his way up a set of stairs during the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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A man carries a hose with the names of fallen emergency personel from 9/11/2001 during the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Attendees of the annual 911 Tower Challenge gather in the field of Arizona Stadium before starting the climb Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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A woman tears up as recordings from 9/11/2001 play during the opening of the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Zach Graham carries an American Flag as he climbs stairs during the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Firefighters make their way down a flight of stairs with other participants of the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Tom Bramel of Bisbee rests following the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Participants run across the field to another set of stairs during the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
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Participants ring a bell following the 911 Tower Challenge at Arizona Stadium Wednesday morning, Sept. 11, 2019. Participants in the annual event climb 2071 steps representing the 110 floors of the Twin Towers in New York City.
Photos: Tucson's 9/11 Tower Challenge at Arizona Stadium
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Photos of people who died at the Twin Towers line the steps as participants take part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
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Participants take part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
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A participant carries the American flag as he takes part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
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Jason Rockwell, with the Pima Regional Bomb Squad, takes a break after climbing stairs with his bomb suit during the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
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Participants take part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
9/11 Tower Challenge
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Participants take part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
9/11 Tower Challenge
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Participants take part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
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Juan Ortiz-Marmolejo, far right, a U.S. Navy veteran, cools off after participating in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2018. First responders, military personnel and civilians climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers.
Photos: 9/11 Tower Challenge in Tucson
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Firefighters from the Tucson Fire Department take part in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017. Participants climbed 2,071 steps to memorialize the first responders who climbed stairs to save people at the Twin Towers. The event was hosted by the 911 Tower Challenge group and 100 Club of Arizona.
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Kirby Comaduran, an engineer with the Tucson Fire Department, salutes as the national anthem is played before the start of the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017.
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Participants sit in the stadium before the start of the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017.
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Robert Wagner, center, a retired firefighter starts his 2,071 step climb with other participants as part of the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017. The event was hosted by the 911 Tower Challenge group and 100 Club of Arizona.
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Participants in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017 make their way up and down the stairs.
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Portraits of first responders who died on Sept. 11, 2001, are posted along the stairs as participants walk past in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017.
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Participants in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017 make their way up and down the stairs.
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Antonio Hirales, 3, holds his hand out to receive high-fives from participants in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017.
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Participants in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017 make their way up and down the stairs.
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Gabriel Dixon performs some stretches after participating in the 9/11 Tower Challenge at Arizona Stadium on September 11, 2017.
Photos: Never Forgotten 9/11 Tower Challenge in Tucson
9/11 Tower Challenge in Tucson
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Tucson firefighters climb the 2071 steps in the west bleachers of the stadium during the 2015 911 Tower Challenge in Tucson, AZ. The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
9/11 Tower Challenge in Tucson
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More than 800 people participated in the 2015 911 Tower Challenge in Tucson, AZ The event honors those first responders who died in the Sept. 11, 2001 attacks. There were 110 floors, 2071 steps in the Twin Towers and you can take the challenge of climbing all 110 floors, all 2071 steps. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Lucas Gabbard of the Tucson Police Department Bomb Squad gets help from his wife Terry Hayward as he suits up to climb 2071 steps at the University of Arizona football stadium during the 2015 911 Tower Challenge in Tucson, AZ Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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More than 800 people participated in the 2015 911 Tower Challenge at the University of Arizona football stadium in Tucson, AZ. The event honors those first responders who died in the Sept. 11, 2001 attacks. To commemorate the 2071 steps in the Twin Towers participants made four complete circuits up and down the stairs in the west bleachers of the stadium. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Tucson firefighters climbed in full gear during the 2015 911 Tower Challenge in Tucson, AZ. The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Members of the the UA ROTC ran the distance during the 2015 911 Tower Challenge in Tucson, AZ. The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Firefighters pass the photo of New York firefighter Michael Fiore, Rescue 5, 46, End of Watch 9/11/01, during the 2015 911 Tower Challenge in Tucson, AZ. Photos of all the first responders who died on 9/11 were posted throughout the stadium seats and fences. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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First responders, families and military join to conquer the steps during the 2015 911 Tower Challenge in Tucson, AZ The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Linda Thursby, whose husband was in the Navy Reserves, takes a break during the 2015 911 Tower Challenge in Tucson, AZ The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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911 Tower Challenge volunteers encourage participants as they make their way through the Ubiversiy of Arizona Football bleachers in Tucson, AZ The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
9/11 Tower Challenge in Tucson
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More than 800 people participated in the 2015 911 Tower Challenge in Tucson, AZ The event honors those first responders who died in the Sept. 11, 2001 attacks. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Volunteer Alyssa Mattus, whose dad Donald Mattus is with DPS, hands out water during the 2015 911 Tower Challenge at the University of Arizona Stadium in Tucson, AZ. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
9/11 Tower Challenge in Tucson
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A firefighter works his way through the 2071 steps during the 2015 911 Tower Challenge at the University of Arizona Stadium in Tucson, AZ. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Probationary firefighter Mark West kisses his daughter during the 2015 911 Tower Challenge in Tucson, AZ The event honors those first responders who died in the Sept. 11, 2001 attacks. There were 110 floors, 2071 steps in the Twin Towers and you can take the challenge of climbing all 110 floors, all 2071 steps. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Plenty of American flags were on hand during the 9/11 Tower Challenge at the UA Stadium, Sept. 11, 2015. Photo by David Sanders/TEP.
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Jennifer Crawford leads a group of employees up the UA Stadium stairs during the 9/11 Tower Challenge, Sept. 11, 2015. Photo by David Sanders/TEP.
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Shea-Lynn Fernald cries as she listens to audio tape from first responders during the actual 9/11. Photo by David Sanders/TEP.
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Don Livingstone, facing camera, was once a Ventura, CA firefighter, hugs TEPâs Wendy Erica Werden at the 9/11 Tower Challenge at the UA Stadium, Sept. 11, 2015. Photo by David Sanders/TEP.
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A firefighter rests his during the 2015 911 Tower Challenge at the University of Arizona Stadium in Tucson, AZ. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
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Christian Chavez, from Davis-Monthan rests following the 2015 911 Tower Challenge in Tucson, AZ. Photo taken Friday, September 11, 2015. Photo by Ron Medvescek / Arizona Daily Star.
