The Tunnel to Towers 5K Run & Walk is an annual event held in various locations across the United States to honor the memory of firefighter Stephen Siller, who lost his life during the September 11 attacks. The event aims to raise funds for the Tunnel to Towers Foundation, which supports first responders and military families in need. Participants can choose to run or walk a 5K distance, often symbolizing the journey that first responders take to protect their communities. The event fosters a sense of community and remembrance, encouraging people to come together to support those who have sacrificed for others.