september 11, 2001, more than 7,000 u.s. service members have died in military operations. during that same time period, about four times as many, more than 30,000 active duty service members and veterans have died by suicide. in tonight s eye on america, cbs s margaret brennan introduces us to a veteran raising money to honor the dead and support the living. you ve got fans. i know. reporter: after four combat tours in afghanistan, retired army colonel chris kolenda wanted to honor his fellow soldiers. so you went from not riding a bicycle in 20 years to riding 1700 miles. i said to myself i m not getting younger. reporter: he biked across country to visit the graves of six paratroopers from the unit he commanded. these are the names of the guys. reporter: how does it feel to have completed it? i feel a lot of gratitude, desperate tude for the service and sacrifice of our six fallen heroes, gratitude for the 800