To cross a stream, road or valley (where by the hold off attributable to a flight of locks at both aspect would be unacceptable) the valley is usually spanned by a navigable aqueduct – a popular illustration in Wales may be the Pontcysyllte Aqueduct (now a UNESCO Entire world https://urso-fofo32109.eedblog.com/37302519/musica-infantil-an-overview