Sept. 10, 2006 — -- For many Americans, the face of evil emerged from the shadows on Sept. 11, 2001, challenging, shaking and shattering some people's spirituality.
But for some, the tragedy renewed their faith in God.
"At times like these, we need to pray with one another," the Rev. James Forbes told his congregation at Riverside Church in New York City five days after the attack.
"People who started with a strong faith, they are able to say this was not God's doing -- this was the doing of some evil, mentally warped, cruel, destructive people," said Rabbi Harold Kushner. "People who were free thinkers and doubted God before that have more evidence to doubt God."
In the immediate aftermath of the attacks, hundreds of thousands -- perhaps millions -- of people flocked to churches, synagogues and mosques seeking solace and a way to comprehend the horror.
"This was an intentional malicious act of humanity against humanity," Atlanta-based Rev. Joseph L. Roberts told Ebenezer Baptist Church on Sept. 16, 2001.
"I believe in God," a parishioner at St. Patrick's Cathedral in New York asked five years ago. "But, I mean, I know you can't blame God. But how can God let his happen?"
"They need something to hang on to, that they can put their anchor in," the Rev. Rick Warren, author of "The Purpose Driven Life," told ABC News. "Inevitably, in time of, of crisis, people turn to their faith."
On Sept. 11, Travis Boyd was just 12-years-old. He was very close to his mother Liz Holmes, who was a single mother.
That morning, she went to work at the World Trade Center. Boyd was still home when his cousin called him.
"She said, 'Travis Boyd, call your mother to see what she's doing or if she's safe, and tell her to get out of the building,' " Boyd said. "I said, 'Okay.' So I called, but no one answered the phone."
His mother never made it out.
Raised as a devout Baptist, Boyd turned to God in his grief.
"I simply said, 'God, I will put it in your hands,' " he said. "You know, I was always brought up by my mother, you know, never to question God. God does things for a reason."
Boyd said he went through a rough period in the year after 9/11. He was often angry and quarrelsome. But he said, to this day, his faith has never wavered.
"I feel that God has not let me down, you know?" Boyd said. "I feel that, you know, he's made me a stronger and better person."
But not everyone affected by the attacks has had that unwavering faith.
The terrorist attacks of 9/11 rocked Marian Fontana's Roman Catholic faith. Her husband, Dave, a Brooklyn firefighter, lost his life trying to save others trapped in the towers.
At age 35, she became a widow -- alone with their 5-year-old son, Aidan.
"I felt angry at God that he would take him and that he would put my son and I through this, so many people through the pain of losing someone," said Fontana, who went on to write the book, "A Widow's Walk."
The anger eventually subsided, but Fontana said when she prays now, she's talking to Dave, not to God.
In the days, months and now years since 9/11, many of the faithful and many of those who lost faith that day say they found something amid the horror that may or may not be God.
To Rabbi Kushner, God can be found in other's responses to tragedy.
"It seems to me the most insightful response is to find the presence of God not in the terrorist act, but in the response of some very brave people," Rabbi Kushner said. "That so many people responded with courage -- to me, that's the presence of God."
Fontana agreed; she found solace in the comforting words of others.
"The outpouring of love I received after 9/11 was beyond any religion," she said. "It buoyed me through my darkest days, my darkest hours. Strangers all over the world, offering their condolences and their love. More than church, more than anything else."