In memorial ceremonies across the nation, and much of the world, people observed a moment of silence in remembrance of the nearly 3,000 victims of the September 11, 2001, terrorist attacks on the United States. The fifth anniversary may be the last one at the Ground Zero site.

Five years after the attacks, much of the focus of the commemorations was on New York where more than 2,700 people died when two hijacked airplanes crashed into the World Trade Center towers, shaking the United States' confidence and changing the New York skyline forever.

As at the previous commemorations at Ground Zero, family members read the names of the dead in a solemn ceremony against a sound track of somber and patriotic music.

Dozens of religious services and commemorative events took place around the city. At one, Mayor Michael Bloomberg said that as New York rebuilds, children must be taught more about the attack than the devastation it wrought.

"We must also share with them the beautiful memories of the loved ones we lost and of the incredible examples of courage we witnessed on that day," said Michael Bloomberg. "And most of all we must share with them our hope for the future, their future. That is how we will truly honor the memory of each of the 2,749 people we lost."

President and Mrs. Bush paid their respects on Sunday, placing a wreath on one of the reflecting pools at Ground Zero. They spent part of Monday morning at a firehouse near the site before traveling to the field near Shanksville, Pennsylvania, where 40 people died after wresting control of hijacked plane. The Bushes then returned to Washington and placed a wreath at the Pentagon site where a fourth hijacked plane killed 184 people upon crashing.

Earlier in the day, Vice President Dick Cheney spoke during a memorial ceremony at the Pentagon.

"We have learned that oceans do not protect us, and threats that gather thousands of miles away can now find us here at home," said Dick Cheney.

The events of 9/11 were commemorated from coast to coast, from religions services in metropolitan cathedrals to makeshift memorials in small towns.

In California, Governor Arnold Schwarzenegger called for a return to the unity Americans experienced after the attacks.

"Let us remember the tragedy but also let us remember the triumph of the American spirit," said Arnold Schwarzenegger.