Floor by floor and step by step, hundreds took on the challenge of climbing Denver's tallest building Sunday, losing their breath for others who struggle to breathe every day of their lives.
About 1,300 people participated in the "Fight for Air Climb" at Republic Plaza, a yearly fundraiser for the American Lung Association in Colorado.
Many climbed in support of friends and loved ones who suffer from lung diseases such as asthma and cancer.
The money raised goes to clean air and lung disease research, education and advocacy.
Fight for Air Climb participants went up more than 50 flights of stairs -- that's 1,098 steps and over 600 vertical feet.
If that wasn't enough of a challenge, some took part in the 'Ultimate Climb," which involves climbing the steps as many times as possible on one hour.
Some local firefighters also climb the stairs in full gear weighing over 45 pounds.
Firefighters have an increased risk for lung disease from the exposure to gases, chemicals and smoke in the line of duty, according to the Lung Association.
Denver7's Lisa Hidalgo, Marc Stewart and Lindsay Watts also took on the challenge.
— lisa hidalgo (@LisaDenver7) February 21, 2016