Twenty years after a day that changed Americans' lives forever, people all across Chicago took part in somber events and paused to remember the 2,996 people who lost their lives that fateful day.
Mayor Lori Lightfoot, Chicago Police Supt. David Brown and other city leaders united for a memorial ceremony where they vowed to never forget the victims and paid tribute to fallen emergency responders.
"These first responders did not hesitate to risk their lives to save others under the worst imaginable circumstances," Brown said.
At Millennium Park, dozens of Marines participated in a 13-mile hike, with one mile representing each U.S. service member who died in an attack at the Kabul, Afghanistan, airport in August.
With the war in Afghanistan over, hikers also honored the servicemen and women who fought for Americans' freedoms during the last 20 years.
"It’s been – wow – I just can’t believe they’ve been in and out of there for that long, and now it’s over," Dana Oswald, president of the Chicago Marines Foundation said. "But it’s never going to be over. We got to remember, and that’s why we are together here today."
Inside Soldier Field, people climbed the equivalent of the 110 stories at the World Trade Center in recognition of those who lost their lives.
"It is amazing to see the support not just from the fire service but for the community to come out," said Roger Bayne Jr., a lieutenant with the Addison Fire Protection District.
Entry fees to the event helped provide funding to the National Fallen Firefighter Foundation, which also organized 40 stair climb events in other locations across the country.
"It gives me goosebumps thinking about that, because as we were doing our opening ceremony this morning, and we were raising flags, we were honoring the fallen, so were so many others," said Laura Haiden, with the Glenside Fire Protection District.
At Navy Pier, volunteers came together and paid it forward by packing hundreds of meals in honor of first responders.