NAPERVILLE, Ill. (CBS) -- Beside the Naperville memorial that bears his name, the parents of Dan Shanower placed a wreath in his honor on Sunday.
The 40-year-old U.S. Navy commander was among the 183 killed when terrorists slammed a plane into the Pentagon where he worked.
"A senseless loss is tough. It's kind of tough," his brother, Jonathan Shanower of Naperville, said.
His family was comforted by a community and a country that honors his life, but they continue to cope.
"There is still that same depth of feeling that comes forward at different times and you are sometimes caught unaware, " Shanower's sister, Paula Coleman, said.
His boss at the Pentagon described Shanower as a top-notch Naval intelligence expert who sprang into action at the first sign of the attacks in New York.
Rear Admiral Richard Porterfield said Shanower's legacy lives on.
"He trained the people that survived the attack and did so many heroic things in the direct aftermath, and it was because of Dan Shanower," Porterfield said.
A tearful Anthony Kosinski, a transplanted New Yorker, felt compelled to be at the memorial Sunday with his daughter.
"I was in New York for 9/11, and I just remember that day and trying to find my friends if they were OK, and thank God they all were, " said Kosinski.
As the flags waved and heads bowed, people remembered not only Dan Shanower but the trying event that arguably made us stronger as a nation.
Perhaps Shanower's sister said it best.
"It certainly very touching to have the number of people present, " Coleman said. "I don't see this as a day about him, but a day about us as Americans being challenged in that way and our need to come together as a country."
The 9/11 Riverwalk Memorial in Naperville is named after Cmdr Shanower and was first dedicated in 2003.
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