43°18′50″N 1°57′24″E / 43.31389°N 1.95673°E
The Grand Bassin is the largest body of open water along the Canal du Midi. It is in Castelnaudary, France and covers some 7 hectares (17 acres). Once a scene of intense economic activity, it is now a major pleasure port used by tourist craft. It holds the water reserve for the four locks of Saint-Roche.
Official opening ceremonies for the Canal du Midi were held here on 19 May 1681. [1]
The basin is exposed to considerable winds, historically even blowing horses and men into the water. A windbreak called Cybele Island ( French: Ile de la Cybelle) was built in 1754. [2] [3] [4] [5]