The Estanys de Vilaüt lakes were part of the deepest area of the old Castelló lake, which occupied a large area of the plain. Once the area has dried up, the deepest part of the lake basin is still more or less permanently flooded, which allows a haven of tranquility for many of the species that can be found there depending on the season. of the year. The maximum splendor of the lake is certainly when the yellow lilies and buttercups bloom, coinciding with the arrival of the summer birds. The lake has a very unique observatory: it was the first bird watching site built in Catalonia (1983) to observe various species of birds.