Genesis 6:14-16

14 Make an ark of cypress wood for yourself. Make rooms in the ark, and cover it inside and out with pitch.

15 And this is how you must make it: The length of the ark will be three hundred cubits, the width of it fifty cubits, and the height of it thirty cubits.

16 Make an opening one cubit below the top of the ark all around; and you must set the door of the ark on the side. Make it with a lower, a second, and a third story.