Thousands of climbers showed up at the CN Tower early Saturday to climb 1,776 steps for the 20th Annual Canada Life CN Tower Climb.
The proceeds of the event go to the World Wildlife Fund, and the climb is the organization's biggest fundraiser of the year.
"We expect about 5,000 people today," said the WWF's Josh Laughren, noting that $1 million could be raised this year.
Despite the daunting prospect of climbing up one of the world's tallest free-standing structures, Laughren said the participants always seem to be in high spirits.
"It's just a great energy," he said.
"You get all types; a lot of the kids don't even look tired when they get to the top."
While many struggle to finish the climb, Laughren said that the vibe at the summit is always electric.
"Even at the top, there is still a great mood of accomplishment and celebration."
Laughren said that the event requires the work of about 400 volunteers, who showed up at the tower at 3 a.m. Saturday to prepare for the climbers.
"It does take the whole year to put together."
Laughren said that on Thursday, about 2,000 people took part in the group climb.
"It's been getting bigger every year," he said.
Since the event began, about 74,000 people have taken part. If you were to tally up all of the distances climbed since the event began, you'd be left with 131 million total steps.
The average time for the climb is about 30 to 40 minutes, organizers said.
But not everyone taking part was trying to set speed records.
For Jack Choros, it was all about finishing the climb for a good cause.
Choros, who has cerebral palsy, normally uses a walker to get around town. For Saturday's trek, he raised more that $2,000 and attacked the challenge with pure adrenalin.
"When people see someone with a disability, they have certain assumptions as to the type of person you are and what you can do for yourself," Choros said.
"I see a lot of people with disabilities who do extraordinary things, and I want to be one of them."
With a report from CTV Toronto's Carol Charles
