New York: Americans prepared to commemorate the 15th anniversary of the September 11, 2001 attacks on Sunday with the recital of the names of the dead, tolling church bells and a tribute in lights at the site where New York City`s twin towers tumbled.
The names of the 2,983 victims will be read slowly by relatives as music plays during a ceremony at the 9/11 Memorial plaza in Lower Manhattan that will pause for six moments of silence.
Four of those mark the exact times four hijacked planes were crashed into the World Trade Center, the Pentagon near Washington D.C., and a Pennsylvania field. The last two record when the North and South towers of the Trade Center collapsed.
The ceremony will be held by two reflecting pools with waterfalls which now stand in the towers` former footprints, and watched over by an honor guard of police and firefighters.
More than 340 firefighters and 60 police were killed on the that sunny Tuesday morning in 2001, in the worst attack on U.S. soil since Pearl Harbor was bombed in 1941.
Many of them died while running up stairs in the hope of reaching victims trapped on the towers` higher floors.
In his weekly radio address on Saturday, U.S. President Barack Obama said it had been one of the darkest days in the history of the nation, but that it underlined the core values and resilience that define Americans.
"We`re still the America of heroes who ran into harm`s way; of ordinary folks who took down the hijackers; of families who turned their pain into hope," Obama said.
"We are still the America that looks out for one another, bound by our shared belief that I am my brother`s keeper, I am my sister`s keeper."
No public officials will speak at the New York ceremony, in keeping with a tradition that began in 2012. The 9/11 Memorial Museum, which sits in the plaza surrounded by white oak trees, will be open on Sunday only to family members of the victims.
Houses of worship throughout the city have been asked to toll their bells at 8:46 a.m. EDT (1246 GMT), the time American Airlines Flight 11 slammed into the North Tower.
A second pause will come at 9:03 a.m. (1303 GMT), when United Airlines Flight 175 struck the South Tower. American Airlines Flight 77 hit the Pentagon at 9:37 a.m. (1337 GMT), then the South Tower collapsed at 9:59 a.m. (1359 GMT).
At 10:03 a.m. (1403 GMT) United Flight 93 crashed near Shanksville, Pennsylvania, and the final moment of silence will be observed at 10:28 a.m. (1428 GMT) when the North Tower fell.
As evening falls across the city on Sunday, spotlights will project two giant beams of light into the night sky to represent the fallen twin towers, fading away at dawn.
Nineteen hijackers died in the attack, later claimed by Osama bin Laden and al Qaeda, which led directly to the U.S. war in Afghanistan and indirectly to the invasion of Iraq.