The national memorial has three main parts: entry, assembly room, and shrine. The central assembly room features seven large open windows on either wall and ceiling, to commemorate the date of the attack. Rumor says the 21 windows symbolically represents a 21-gun salute or 21 Marines standing at eternal parade rest over the tomb of the fallen, but guides at the site will confirm this was not the architect's intention. The memorial also has an opening in the floor overlooking the sunken decks. It is from this opening that visitors can pay their respects by tossing flowers in honor of the fallen sailors. In the past, leis were tossed in the water, but because string from leis poses a hazard to sea life, leis now are placed on guardrails in front of the names of the fallen.