A baby hatch (also called foundling wheel) is a system where parents can leave infants for adoption anonymously. Such systems were in use since the Middle Ages. Baby hatches are usually installed at hospitals. There, mothers or fathers can put their newborn baby into the hatch. The hatches are usually in hospitals or social centers or churches and consist of a door or flap in an outside wall which opens onto a soft bed, heated or at least insulated. Sensors in the bed alert carers when a baby has been put in it so that they can come and take care of the child. It will be cared for by hospital staff. If it is not claimed within a given time period, it will be given up for adoption. These hatches are popular in Germany and Pakistan.