The man who was commissioner of New York City’s fire department when the World Trade Center towers fell says the event has changed attitudes.Tom Von Essen, who spoke yesterday at the Iowa Bankers Association convention in Des Moines, says world opinion of heroes has changed a lot since 9/11. Three-hundred-41 fire fighters and E-M-Ts from Von Essen’s department died September 11th. Von Essen says he’s uncomfortable being called a hero, as he believes the true heroes are those who didn’t go home that day.Von Essen says it wasn’t just people who wore a badge or a uniform who were heroes that day. He says everyday people risked their necks when the chips were down.Von Essen read some of the names of the 9/11 victims during the ceremony a week ago at Ground Zero.Von Essen says citizens from 83 different countries were killed in the Trade Center tragedy and seeing the “different shades of color and shapes and sizes and ethnic clothing” of relatives who went to the ceremony gave him another perspective on how horrible the event really was. Von Essen recently retired and works in former New York Mayor Rudy Guiliani’s firm. Von Essen wrote a book about his 9/11 experiences, entitled “Strong at Heart.”