Thursday marks the 76th anniversary of the attack on Pearl Harbor by the Imperial Japanese Navy on the morning of Dec. 7, 1941. The attack in Hawaii claimed more than 2,400 American lives and brought the United States into World War II.

Hundreds of Japanese warplanes and submarines targeted the U.S. naval base and sank four battleships and two destroyers. The 90-minute-long attack damaged many other aircraft, buildings, and ships. The next day U.S. entered World War II and then-President Franklin D. Roosevelt delivered one of the most important speeches in U.S. history.

"Yesterday, December 7, 1941,—a date which will live in infamy—the United States of America was suddenly and deliberately attacked by naval and air forces of the Empire of Japan," he said to open his remarks declaring a state of war to Congress, following which a resolution was approved that recognized the U.S. was at war with Japan.

Pearl Harbor Day is observed every year in the United States on Dec. 7 to remember the tragic day for Americans. Below are some quick facts about the day.

1. Almost half of the casualties at Pearl Harbor were on the naval battleship USS Arizona which was hit four times by Japanese bombers and eventually sank.

2. All 21 members of the Arizona’s band, known as U.S. Navy Band Unit (NBU) 22, who were aboard the USS Arizona, died.

3. The first wave of attack consisted of 183 planes, but six failed to launch.

Pearl Harbor Day Pictures U.S. President Frankin Delano Roosevelt signs the declaration of war on Japan in Washington, DC, Dec. 8, 1941. Photo: U.S. National Archives/Handout via Reuters

4. The Japanese traveled 3,400 miles across the Pacific to execute their attack on Pearl Harbor.

5. The Japanese forces were led by Vice Admiral Chuichi Nagumo.

6. The day before the attacks, the USS Arizona took on a full load of fuel, nearly 1.5 million gallons.

7. According to the History Channel, Arizona "continues to spill up to 9 quarts of oil into the harbor each day."

8. The Pearl Harbor attack led to eight investigations between Dec. 22, 1941, and July 15, 1946.

Pearl Harbor Day Pictures The damaged battleship USS California listing to port after being hit by Japanese aerial torpedoes and bombs. Seen off Ford Island during the attack on Pearl Harbor, Hawaii, Dec. 7, 1941. Photo: U.S. National Archives/Handout via Reuters

9. The Japanese lost 65 men with an additional soldier being captured.

10. “Remember Pearl Harbor!” became a rallying cry for the U.S. during World War II.

Seventy-six years later, some worry most Americans don't recognize the importance of Dec. 7, 1941.

"On December 7, 1942, sailors and civilian workers gather at the USS Arizona (BB-39) to pause, reflect and remember those who were killed in Pearl Harbor. A single pole displays an American flag that flutters in a Hawaiian breeze. It is the first of 76 years of remembrances to follow. This year we remember a nation rising to the challenge to eventually create a peaceful and free Japan and Western Europe. Today, here in Pearl Harbor, we celebrate the peace shared between the United States and Japan and all our friends and partners," a remembrance message on the Pearl Harbor Day official website reads.