Flags were lowered as America marked the 70th anniversary of Japan's attack on Pearl Harbor, which thrust the United States into World War II, changing the course of history.
Ceremonies were scheduled from Pearl Harbor in Hawaii to Washington DC on the US East Coast to remember the 2,400 Americans who died on December 7, 1941 when Japan launched a devastating surprise offensive on the US Pacific Fleet.
President Barack Obama called for the Stars and Stripes to be flown at half mast on federal buildings across the country, to mark National Pearl Harbor Remembrance Day.
"We salute the veterans and survivors of Pearl Harbor who inspire us still. Despite overwhelming odds, they fought back heroically, inspiring our nation and putting us on the path to victory," Obama said in a statement.
"They are members of that Greatest Generation who overcame the Depression, crossed oceans and stormed the beaches to defeat fascism, and turned adversaries into our closest allies."
Obama said that generation then came home at the end of the war in 1945, went to college and went on to build the largest middle class in history and the strongest economy in the world, entwining his remembrance with a call for modern-day unity.
At exactly 7:55 am (0:655 NZT) on the fateful day, Japan awakened the American "sleeping giant," bombing the US Pacific Fleet anchored in Hawaii. In two hours some 20 ships were sunk or damaged and 164 planes destroyed.
Of the 2,400 who died, nearly half were killed in a matter of seconds aboard the giant USS Arizona battleship, when a bomb detonated the ship's munitions depot, igniting a conflagration that burned for three days.
Denouncing "a date which will live in infamy," president Franklin Roosevelt declared war on Japan, leading the United States into World War II at a time when many of his countrymen had hoped to avoid the conflict.
For seven decades, some conspiracy theorists have believed that president Roosevelt had received intelligence about the Japanese attack before it happened, but willingly chose not to act on it.
The theory goes that Roosevelt believed the shock of the attack would persuade Americans of the need to enter the war.
The theory is based on the fact that US military radar failed to detect the approach of six Japanese aircraft carriers with 400 planes on board, which stopped 220 miles (350 km) from their target.
But the theory has been dismissed by some experts.
"It's a legend," says military historian Daniel Martinez, who works for the Pearl Harbor National Monument in Hawaii. "This is the kind of conspiracy theory fabricated for the profit of writing a book."
"He wanted war to happen with Germany," explained Martinez. "The last thing he needed was a two-front war."
Whatever the truth, the day after Pearl Harbor, the US Congress officially declared war on Japan. Three days later, Germany declared war on the United States. The US entry into the war was to change the course of the conflict.
In Pearl Harbor on Wednesday, just west of Honolulu, a handful of USS Arizona survivors will join other military veterans to salute those who died in the attacks, an annual ceremony made more poignant by the 70th anniversary.
In Washington, where a ceremony is scheduled at the US capital's World War II Memorial, Hawaiian-born Obama paid tribute to the fallen, and drew parallels to the current "9/11 generation" which went off to war in Afghanistan and Iraq following the September 11 attacks in 2001.
"We resolve to always take care of our troops, veterans and military families as well as they've taken care of us," Obama said.
Republicans vying for the chance to succeed Obama in the White House also issued statements observing the historic date.
Congresswoman Michele Bachmann in a tweet urged her supporters to "please remember the victims of the #PearlHarbor attacks. The 'date of infamy' that forever changed America happened 70 years ago today."
Texas Governor Rick Perry also sent out a Twitter message saluting veterans of the attack."