To cross a stream, highway or valley (where the delay attributable to a flight of locks at both aspect might be unacceptable) the valley might be spanned by a navigable aqueduct – a popular example in Wales is the Pontcysyllte Aqueduct (now a UNESCO Environment Heritage Internet site) over https://soprador-para-limpar-pc97418.blogdosaga.com/37009228/little-known-facts-about-musica-infantil