As New York slept, ceremonies to mark the anniversary of 11 September in the Asia-Pacific region began at dawn in New Zealand.
There a lone bugler played as the Stars and Stripes was raised over Auckland harbour bridge.
Later a choir started a relay performance of Mozart's Requiem which will encircle the globe.
The performance will last for 24 hours, with choirs in 20 time zones, each beginning it at 0846 - the time the first plane hit in New York.
A flag of a different kind was on display in Surfer's Paradise, Australia, where about 3,000 people turned out to form a human Stars and Stripes on the beach.
Across the country sirens wailed, construction workers downed tools and motorists turned on their headlights in tribute to the thousands killed.
For those working in the emergency services it was an especially poignant time as they attended special church services to pay tribute to hundreds of American colleagues who died at the World Trade Center.
The first commemoration of the anniversary on US soil was on the Pacific island of Guam - known as the place where America's day begins.
Locals and members of the US military stationed there gathered in front of the governor's residence as a gun salute was fired.
This time last year the gates of the US embassy in Japan were a gathering point for those who wanted to express their grief over the 11 September attacks, laying flowers and folded paper cranes - the sign of longevity - on the ground.
Now one year on they returned to the same spot to watch as Nancy Kassebaum Baker, wife of US ambassador Howard Baker, planted a single maple tree to provide a living memorial to the victims.
With the opening words "requiem aeternam dona ets, Domine, et lux perpetua luceat ets," - "grant them eternal rest, O Lord, and may perpetual light shine on them," a choir in Taiwan began their stage of the global Mozart Requiem.
Even staff working at the Scott-Amundsen Base at the South Pole joined in with the 15,000 participants.
The requiem will end in American Samoa.
But for most across the region the one-year anniversary of the attacks was simply a time for quiet contemplation as they paused and remembered the thousands that lost their lives.