Thursday Dec. 7 marks National Pearl Harbor Remembrance Day, and is the 82nd anniversary since the attack in Hawaii that began the U.S.'s involvement in World War II.

On Dec. 7, 1941, the Japanese military made a surprise attack on the United States Naval Base at Pearl Harbor in Hawaii, which resulted in the deaths of thousands of service members and civilians, over a thousand injuries, the sinking of American ships and destruction of aircrafts. The next day, the U.S. declared war on Japan and entered into World War II.

Here's what to know about National Pearl Harbor Remembrance Day.

When is National Pearl Harbor Remembrance Day?

National Pearl Harbor Remembrance Day is observed on Dec. 7 every year, the anniversary of the attack by the Japanese military on the naval base in Hawaii.

Commemorations are held every year in Hawaii and across the country to mark the day, and American flags will be flown at half-staff.

When was Pearl Harbor? What happened?

The Japanese military attacked Pearl Harbor with no warning on the morning of Dec. 7, 1941.

At the time of the attack, Hawaii was still a territory and not yet a U.S. state. President Dwight D. Eisenhower- would later sign a proclamation in 1959, officially admitting Hawaii as the 50th state.

According to the National Park Service, 2,403 service members and civilians were killed and another 1,178 people were injured in the attack. Two U.S. Navy battleships – the USS Arizona and the USS Utah – were also permanently sunk, and 188 aircraft were destroyed.

The U.S., under President Franklin Roosevelt, declared war with Japan the next day and officially entered into World War II. Roosevelt would famously call the date of the attack "a date which will live in infamy."

How many people died in Pearl Harbor?What to know about the casualties in 1941 attack.

When was the first National Pearl Harbor Remembrance Day?

U.S. Congress designated Dec. 7 as National Pearl Harbor Remembrance Day on Aug. 23, 1994, according to the National Park Service.

Remembrance events are held every year at the Pearl Harbor National Memorial in Hawaii, leading up to the commemoration ceremony, held on Dec. 7.

Where is Pearl Harbor?

Pearl Harbor is a naval base, located on the island of Oahu in Hawaii. It is still an active military base and is the headquarters of the Pacific Fleet.

It is also the location of a National Historic Landmark which commemorates the attack on Pearl Harbor, the war in the Pacific and the eventual surrender of the Japanese on the deck of the USS Missouri in 1945.