In New York and Washington, the first of what will be thousands of funerals took place, each of them packed with mourners and watched by millions across the country.
Most poignant of all was the funeral in New York of Father Mychal Judge, the Irish-American Franciscan priest who was the chaplain to the city's fire department.
The 67-year-old chaplain was killed when the twin towers collapsed as he gave the last rites to a firefighter.
He had rushed in a fire truck to the scene of the attacks as soon as emergency services were called to respond and worked to comfort people before he too became a victim.
Hundreds of firefighters from across north-east America stood at attention outside his church, itself opposite a fire station, as his funeral, led by New York's cardinal, Mr Edward Egan, and attended by Mayor Rudolph Giuliani.
"The best way to describe him was your ultimate Irishman from Brooklyn a warm, loving personality and at the wake service last night everyone who met him said they felt like his best friend," said Fr Brian Jordan.
"His duties really began after the tragedies, after the fires had been put out. He continued to minister to the families and the firemen. Some of the people who have been here talked about how he helped them through so much.
"The firemen who found him laid on a body board and took him to St Peter's Church, laid him in front of the altar, laid a sheet over him and put his badge on top of it.
"Some of the firemen were already coming in to pay their respects to him. They were Michael's family. The body was actually brought back to the firehouse and the guys received him with great reverence."
Funerals were also due for fire chief Mr Peter Ganci and some of the other 300 firefighters were killed as the towers collapsed.
Senior ranks of the fire department suffered heavy losses as they made their way to a command centre, ironically located in the World Trade Centre.
They had been speaking to Mayor Giuliani and police commissioner Bernard Kerick before they died and the city's leader and police top brass cheated death by just minutes as they walked away from the twin towers before they collapsed.
PA