Banana is the small port settlement near the mouth of the Congo River, a few kilometres from Moanda. Its name appears often in older Congo history because this was one of the first Atlantic footholds for European traders and administrators in the lower Congo.
Today it is a modest, workaday place rather than a sightseeing town. The interest is geographic: river, ocean, oil infrastructure, and a thin line of coast all meet here. Go with a local driver and treat it as part of a wider coastal loop rather than a standalone destination.