A bridge tower (German: Brückenturm) was a type of fortified tower built on a bridge. They were typically built in the period up to early modern times as part of a city or town wall or castle. There is usually a tower at both ends of the bridge. During the 19th century, a number of bridge towers were built in the Gothic Revival style – Tower Bridge in London is perhaps the best known example; however, many original medieval towers survive across Europe.