A 500-mile walk honors 9/11 first responders
Frank Siller is marking the 20th anniversary of the September 11 attacks by walking 500 miles from the Pentagon in Washington, D.C., to Ground Zero in New York City. Siller's brother Stephen was a firefighter who ran through the Brooklyn Battery Tunnel to the World Trade Center with 60 pounds of gear strapped to his back. He later died trying to rescue people from the towers. Frank Siller, CEO of the Tunnel to Towers Foundation, joins CBSN's Tanya Rivero to discuss why this walk is about more than remembering his brother.