NEW YORK (PIX11) — Hundreds of courageous people woke up at the crack of dawn Sunday to celebrate the life and sacrifice of Sept. 11 heroes.

During the pandemic, the “Tunnel to Towers” climb was put on hold, but now the iconic challenge returns to One World Observatory in Manhattan. For each of the 2,226 stairs climbed, a 9/11 hero is honored.

“It’s tremendous anybody who gets up at 5 in the morning to willingly do this, it speaks a lot of their character,” said Erika Oelkers.

Oelkers, of Long Island, served as the honorary starter for the climbs at One World Observatory.  She is participating in memory of her husband, Thomas, a 19-year veteran of the FDNY. 

Last May, Thomas lost his battle against a 9/11-related illness, forever changing the lives of Erika and her two daughters. 

“Watching my husband be sick and see him pass was the most difficult thing they ever experienced in their life and probably will,” said Oelkers.

After a two-year hiatus, the “Tunnel to Towers” Foundation welcomed back participants who challenged themselves to climb 104 flights.

“I lived in New York for over a decade and I think it’s a great tribute to have this physical exertion as a way to remember the people we lost,” said participant, Verity Rees.

The foundation is dedicated to honoring the sacrifice of FDNY Firefighter Stephen Siller, who laid down his life to save others on September 11, 2001.

Stephen’s brother, Frank Siller, is the CEO of Tunnel to Towers.

“What’s more iconic than this building in America and to climb up the stairwell because we know what those stairwells signify, the sacrifice made 20 years ago,” said Frank Siller.

For more than 20 years the foundation has supported injured vets, first responders, and their families left behind. By the end of 2022, “Tunnel to Towers” will deliver 1,000 mortgage-free homes to our nation’s heroes. 

“My husband would have had peace of mind knowing there was one thing less on my plate,” said Oelkers.

Oelkers is thankful her mortgage is now paid off, as the memory of her fallen hero lives on through the sweat, sore feet, and painful muscles of these brave souls.

“Every step you think is difficult, that memory clicks in and you faster,” said participant, Dan Strader.