Channel through which circulates the water or sewage, oil or gas. It's a conduit of various shapes and sizes, usually cylindrical. Children are the ones located in households and the larger in proportion to the amount of the element lead, are those who are in the basement. In particular, there are pipelines, gas pipelines, more current and modern system leading oil and gas, respectively, without forgetting the aqueducts, procurement system of water historically created by the Romans, and in Segovia, province Spanish, you will find one very well-preserved and worth a visit.