The ceremony began at 8:40 in New York, when, ten years ago, a Boeing 767 of American Airlines hit the North Tower of World Trade Center.
At sunrise, a huge American flag was held on the facade of One World Trade Center , which currently has six floors and is set to become the highest tower in the U.S.
In a surreal silence, work on the site ceased and traffic was interrupted in this area of Manhattan.
Barack Obama and George W. Bush arrived together with their wives at the site of Ground Zero, where families of the victims of the attack had gathered. The Head of State, his predecessor and the two first ladies watched in silence before the memorials built at the site of the two towers and put their hands on the plaque in memory of the victims.
This area of eight acres, planted with over 200 oak trees, has two 50ft-deep pools with fountains, built on the exact spot where the twin towers stood. The names of the victims are carved into a dark parapet on the edges of the pools.
Moments of silence were held at 8.46am and 9.03am , when hijackers flied the planes into the two towers. Similar moments of silence were also planned at 9.36am and 9.59am in the Pentagon and in the field of Pennsylvania, Shanksville, where Flight 93 crashed, killing all 40 passengers, the crew and the four hijackers.
Two more were held at 10.03am and 10.28am when the two towers fell.
President Obama read Psalm 46 from the Bible. Standing behind bulletproof glass near the 9/11 memorial’s white oak trees, he read aloud: “God is our refuge and strength. He dwells in his city, does marvelous things and says, be still and know that I am God.”
The victims’ families took the floor to read the names of the 2,753 people killed on Sept. 11. This reading, interrupted by moments of silence, lasted several hours. Several musical interludes interspersed during the reading of the victims’ names.
Former president George W. Bush read a letter written by Abraham Lincoln to a mother who had lost five sons during the Civil War.
The families of the victims gathered around the site, some wearing T-shirts bearing the image of their loved ones who had died. Many brought with them flowers, photos, teddy bears and flags in honor of the victims.
Security measures have been consolidated in New York because of possible threats planned by al-Qaida.
Ceremonies were held in many other places around the world.
In New Zealand , the players and audience at the Ireland-United States match in the Rugby World Cup held a moment of silence in the Taranaki stadium in New Plymouth.
U.S. Ambassador to New Zealand, David Huebner, paid tribute to Mark Bingham and Jeremy Glick, two rugby players who participated in the revolt aboard the hijacked United 93 plane that and crashed into a field in Pennsylvania.
The New York Times dedicated an entire article to counting the billions of dollars invested in security, wars, the economic impact of the attacks and the cost in human lives.
“Al Qaeda spent roughly half a million dollars to destroy the World Trade Center and cripple the Pentagon. What has been the cost to the United States ? In a survey of estimates by The New York Times, the answer is $3.3 trillion, or about $7 million for every dollar Al Qaeda spent planning and executing the attacks,” half of which was used to finance the costs of wars. “This total equals one-fifth of the current national debt.”