WASHINGTON -- Commemorations are under way at Joint Base Pearl Harbor-Hickam, Hawaii, and in Washington, where Defense Secretary Leon E. Panetta placed a wreath at the Navy Memorial in memory of those killed 70 years ago Wednesday during the attack on Pearl Harbor.
Until Sept. 11, 2001, the surprise early-morning attack on Dec. 7, 1941, stood as the most devastating enemy attack on U.S. soil.
Within hours, more than 2,400 Americans were dead. Five of the eight battleships at the U.S. Fleet's Pearl Harbor base were sunk or sinking, and the other battleships, as well as ships and Hawaii-based combat planes, were heavily damaged.
By crippling the U.S. Pacific Fleet, Japan hoped to eliminate it as a threat to the Japanese Empire's expansion south.
What the enemy hadn't counted on was that the Pearl Harbor attack would become a defining moment in U.S. history, rallying the American people against their attackers.
President Franklin D. Roosevelt declared Dec. 7, 1941, "a day which will live in infamy" and signed the Declaration of War against Japan the following day.
It was the start of a long, difficult war against tyranny. Nazi Germany, which already controlled a vast empire, declared war on the United States four days later.
President Barack Obama, in his National Pearl Harbor Remembrance Day 2011 proclamation, heralded the resilience the military demonstrated in the face of the aggressive attack.
"As explosions sounded and battleships burned, brave service members fought back fiercely with everything they could find," he said.
Panetta, speaking last week at a gala commemorating a centennial of naval aviation, called the response to the attack -- the beginning of the Pacific campaign of World War II -- one of the finest chapters of American military history.
"It was a time for bold offensive action, for daring in the face of grave risk and for innovation when it mattered most," he said, praising the force that "fought back from that terrible attack and reclaimed the Pacific, one bloody battle after another."
The secretary recalled how Navy Adm. Chester W. Nimitz, commander of U.S. Pacific Fleet during the war, vowed at Midway to "greet our expected visitors with the kind of reception they deserve."
"And so he did," the secretary said. "Nimitz outmaneuvered the enemy fleet with only three available carriers and turned back the Japanese offensive."
Navy Secretary Ray Mabus, who took part in Pearl Harbor commemoration events in Hawaii, shared Panetta's admiration for the "vision and skill and courage" the U.S. military demonstrated when its homeland faced attack.
They faced the adversary head-on, turning the tide of the war six months later at the Battle of Midway. Mabus noted that naval historian John Keenan has called the fight there "the most stunning and decisive blow in the history of naval warfare."
Seventy years later, Mabus said the response to the Pearl Harbor attack continues to give pride and inspiration to the fleet. It helped lay an example for today's sailors and Marines who he said constitute "the best expeditionary fighting force -- on the sea, under the sea, above the sea, on the land, over the land -- that the world has ever known."
Panetta, in a message to Pearl Harbor survivors released Tuesday, thanked them for setting the standard for those who followed in their footsteps and continue to defend the United States today.
"I know you take great pride, as I do, that your legacy lives on in today's men and women in uniform, who have borne the burden of a decade of war, and who are truly this nation's next greatest generation," he said. "Your example inspires those in uniform today, strengthens our nation's moral fiber and proves that with united resolve, our country can surmount any challenge."
Panetta thanked the Pearl Harbor survivors for ensuring the memory of their fallen comrades lives on.
Seven decades after the attack, visitors can still see evidence of the destruction. The runway at Ford Island and hangars at Hickam Air Force Base show bullet holes from the Imperial Japanese fighter planes' barrage. Beads of oil from the sunken USS Arizona -- above which stands the USS Arizona Memorial -- still trickle to the water's surface.
Wednesday in Pearl Harbor, survivors, military officials and others continued the commemorations that began earlier in the week to reflect on the attacks 70 years ago. They paused for a moment of silence at 7:55 a.m. Hawaii time, the exact time the attack began, to remember those lost.