CHICAGO (WLS) -- One step at a time, more than 2,000 people from all around the world converged on Willis Tower to climb up the world's 12th tallest building.
Sunday marked the 16th SkyRise Chicago, which raises more than $1 million each year for Chicago's Shirley Ryan AbilityLab.
The world-renowned research hospital helps people with severe injuries, complex conditions and diseases.
"Seeing them being able and accept the challenge and finish the challenge is an amazing achievement," Aleksandra Gebska with Shirley Ryan AbilityLab said.
Current and former Shirley Ryan AbilityLab patients took on the challenge to highlight the best of human willpower and grit.
"I didn't know if I was going to be able to walk. I was anticipating maybe being in a wheelchair permanently," former Shirley Ryan AbilityLab patient Moira Ledesma said.
Ledesma completed SkyRise Chicago for the first time with her boyfriend after recovering from a spinal cord and brain injury.
Hours of occupational and physical therapy led to her triumph on Sunday more than 1,300 feet in the sky.
"It's a beautiful thing just pushing your body. You just don't know what you can do," Ledesma said.
"The research shows consistent exercise slows the progression," Shirley Ryan AbilityLab patient Denise Cary said.
Denise Cary was diagnosed with Parkinson's disease five years ago. Sunday was her second time climbing in SkyRise Chicago. She says it's all thanks to the Shirley Ryan AbilityLab.
"They told me there's no cure but we can delay the progression the disease. Follow our lead. And I have. I'm here," Cary said.
Mike Dineen said he has participated in SkyRise Chicago since it's first event 16 years ago.
Dineen went into a coma for three weeks after a car accident in 2009. Afterwards, he worked on rehabilitation at Shirley Ryan AbilityLab.
After six months of rehab, he was able to get back to work.
"When I got out of the hospital, the first thing the surgeon said to me, 'Mike, I'm glad to see you walking and talking, cause you are supposed to be dead'," Dineen said.