Few incidents leave a permanent mark on our minds. When we try to forget them, it's not easy for us to do so. September 11th attacks are one of such incidents. These memories are so painful that their pain can still be felt. The video we are showing you today, it might be hard for you to watch it.
This haunting footage shows first responders who are walking into twin towers just moments before the collapse.
"Even 15 years later, this tribute to First Responders on September 11th is hard to watch... but it's so important. Never Forget."