President Bill Clinton declared Dec. 7, 1994, the first National Pearl Harbor Remembrance Day.
Though it is not a federal holiday, the American flag is flown at half-staff until the sun sets in honor of those who died as a result of the surprise attack.
Visitors often flock to the island of Oahu to commemorate the day. There, a series of memorial ceremonies are scheduled on historic Pacific Fleet sites.
What exactly happened on Dec. 7, 1941?
Just before 8 a.m. on that Sunday morning, Japanese forces led a surprise attack on Pearl Harbor, a U.S. naval base near Honolulu, Hawaii, bringing with them hundreds of fighter planes.
It began with a first wave of 183 planes, followed by a second wave of 171 planes, all with varying targets. A third wave was initially considered, but later withdrawn.
Thousands of Americans died in the less than 90-minute assault, including civilians. Another thousand were wounded.
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Why did Japan attack Pearl Harbor?
Though the attack was a surprise, U.S.-Japan relations had been tense for decades.
During World War II, History.com scholars say Japanese Emperor Hirohito played a pivotal role in transitioning his country from "rising democratic sentiment" to "ultra-nationalism and militarism."
In 1937, Japan declared war on China and massacred an estimated 200,000 civilians and prisoners of war near the Manchurian city of Nanking.
The country also allied itself with Nazi Germany and sent troops to French Indochina soon after signing the Tripartite Pact with Germany and Fascist Italy, which resulted in U.S. trade embargoes on oil, metal, aircraft exports and more.
The U.S. also provided economic support to Guomindang forces in China, who were fighting Japanese troops in the infamous Nanjing Massacre.
American leaders hoped the sanctions and enemy support would warn Japan to stop its expansionism, but it only further angered Japan, turning its people against the West’s interference in the wars.
By then, “war with the United States had become to seem inevitable, in order to defend [Japan’s] status as a major world power. Because the odds were stacked against them, their only chance was the element of surprise,” according to History.com.
The naval base at Pearl Harbor, which became America’s main base in 1940, was “left relatively undefended, making it an easy target.” Americans didn’t expect the Japanese to attack Hawaii as it’s 4,000 or so miles from the Japanese mainland.
How many fatalities resulted from the Battle at Pearl Harbor?
According to the National WWII Museum, a total 2,403 U.S. personnel, including 68 civilians, were killed in the attack. Another 1,178 were wounded.
Japan lost 129 soldiers.
Was the attack on Pearl Harbor considered a success for Japan at the time?
Though Japanese forces were able to cripple the Pacific Fleet on Dec. 7, 1941, they were not able to completely destroy it. In fact, Japanese bombers missed several American oil tank farms, submarine bases, navy repair facilities, ammunition sites and aircraft carriers.
"This failure came to haunt the Japanese, as U.S. forces scored a major victory in the Battle of Midway, decisively turning the tide of war in the Pacific," according to History.com.
How did America react to the attack?
The surprise assault launched the U.S. into World War II.
On Dec. 8, 1941, President Franklin D. Roosevelt proclaimed Dec. 7, 1941, “a date which will live in infamy” and called for a formal declaration of war on Japan.
“No matter how long it may take us to overcome this premeditated invasion, the American people in their righteous might will win through to absolute victory,” Roosevelt said in the speech before the U.S. Congress. “I believe I interpret the will of the Congress and of the people when I assert that we will not only defend ourselves to the uttermost, but will make very certain that this form of treachery shall never endanger us again.”
Germany and Italy declared war on America three days later, and the U.S. responded with the same.
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Roosevelt also ordered the internment of 110,000 to 120,000 Japanese Americans following the attack, a policy that involved forced deportation and incarceration with the goal of preventing espionage within America.
Canada followed suit shortly after Roosevelt’s executive order.
Even those with as little as 1/16 heritage — or orphaned infants with “one drop of Japanese blood” — were placed in internment camps. The majority of Japanese Americans at the time were U.S. citizens.
The internment camps, which gave rise to anti-Japanese racism in the country, are “now considered one of the most atrocious violations of American civil rights in the 20th century,” according to History.com.
Why was America so unprepared for the attack on Pearl Harbor?
Credit: AP Photo/Audrey McAvoy
Credit: AP Photo/Audrey McAvoy
Some military officials, including Maj. Gen. Sherman Miles, had pointed out Pearl Harbor's vulnerability to attack. But "we underestimated Japanese military power," he wrote for The Atlantic in 1948.
“It has since been implied that the reason Hawaii was not on the alert was that Washington thought the Japanese would not attack there. That suggestion points up very neatly the crucial issue. For the opposite was true -- Washington thought the Japanese would not attack Hawaii largely because it believed Hawaii was alerted and prepared.
That was, admittedly, an assumption, but it was so fundamental an assumption, based on so many years of indoctrination, as well as on issued orders, that it was not questioned by anyone in Washington, from the President down. For guns don't shoot or planes fly by themselves.”
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When Roosevelt decided to move much of the Pacific Fleet to Pearl Harbor, one protesting admiral was removed from command.
Such warnings gave rise to conspiracy theories arguing British and American governments knew of the attack and allowed it to happen to get the U.S. involved in the war.
Learn more about Pearl Harbor at History.com.