According to Genesis, what was the Ark's only entrance?

According to Genesis, the Ark had a door in its side. Genesis 6:16 includes this detail among the construction instructions given to Noah.

The verse describes the Ark’s opening alongside its three decks and an upper opening or window. Genesis 7:16 later says that Noah entered the Ark and that God shut him in, reinforcing the importance of the side door in the narrative.

Popular paintings and models often add multiple entrances, ramps, or prominent roof openings for practical or artistic reasons. Genesis itself does not describe several doors. Its concise architectural description identifies one door in the side, an opening near the top, and three levels inside.