Madrid has historically obtained its water from mountains through underground canals, wells, and the Manzanares River since medieval times. In the 19th century, dams like the Pontón de la Oliva Dam began to be built to supply water. The El Canal de Isabel II, Madrid's most important canal, was constructed starting in 1851 and is over 70 meters long. It now supplies water to Madrid from local aquifers during dry periods. Historically, there were public fountains and water carriers delivered water to homes, while washing places along the Manzanares River and public baths provided hygiene facilities before modern plumbing. Access to safe, clean water remains an issue today for some.