Genesis 6:15-17

15 And this is the way you are to make it: the length of the ark shall be 300 cubits, its breadth 50 cubits, and its height 30 cubits [that is, 450 ft. x 75 ft. x 45 ft.].

16 You shall make a roof or [2]window [a place for light] for the ark and finish it to a cubit [at least 18 inches] above — and the [3]door of the ark you shall put in the side of it; and you shall make it with lower, second, and third stories.

17 For behold, I, even I, will bring a flood of waters upon the earth to destroy and make putrid all flesh under the heavens in which are the breath and spirit of life; everything that is on the land shall die.