Canal du Midi
The Canal du Midi  is one of the oldest canals of Europe still open. It is 240 km (150 miles) long, going from Toulouse, where it meets the Canal de Garonne, to the Mediterranean where it joins the Étang de Thau, a large lake.  It was built from 1666 to 1681, during the reign of Louis XIV.   It joins the Mediterranean and the Atlantic ocean.  Many earlier plans had been made, but were not built because of the difficulty of getting water to supply the highest level. A reservoir was built with a large dam at Bassin de Saint-Ferréol.  The dam is 780 metres (2,560 feet) long, with a maximum height of 32 metres (105 ft), and a base thickness of more than 140 m (450 ft).  It was the largest work of civil engineering in Europe and only the second major dam to be built in Europe. Nearly 12,000 people worked to build it.