In Genesis, Noah built a door into the side of the Ark.
Genesis 6:16 describes the Ark’s layout and says that its entrance was to be placed in the side. The same passage also mentions a roof or opening and three levels, while the door provided the practical access point for Noah, his family, and the animals.
The wording matters because many artistic depictions show large ramps, multiple doors, or elaborate ship entrances. Those features may make visual or engineering sense, but Genesis specifically mentions one door in the side. The text does not provide a detailed hinge design, dimensions for the doorway, or a diagram of how it worked.
In Genesis 7:16, after the occupants enter, the text says that the Lord shut Noah in. This detail has led to religious interpretations about divine protection, but it does not change the architectural answer: the named feature is a door in the Ark’s side.