The Ha'penny Bridge (officially known as the Liffey Bridge from the river that flows beneath it) is a single-span cast iron pedestrian bridge erected in 1816 as an alternative to a ferry connecting the city’s north and south sides. It is the most famous among the roughly 24 bridges serving the needs of pedestrians and vehicles crossing the River Liffey (about sixteen are within the city’s limits). It is considered an international icon associated with Dublin.