Dublin's most famous bridge is the Ha'penny Bridge, built in 1816. One of the world's oldest cast-iron bridges, it was built to replace the seven ferries that plied a busy route between the two banks of the river. Officially known as the Liffey Bridge, it gets its name from the ha'penny (half penny) toll that was charged until 1919 (for a time the toll was one-and-a-half pence, and so it was called the Penny Ha'penny Bridge).