This site, also known as the lagoon of Santa Cristina, used to be an open-pit mine for the extraction of the thin materials needed to make bricks. It occupies almost four hectares of water space and is about 20 metres deep in the centre, possibly making it the largest in Pontevedra. When extraction activities ceased in the late 20th century, groundwater and rain began to fill the excavated area until it reached its current shape. The lagoon was colonised by marsh vegetation and animals and organically turned into a wetland. It is an example of the transformation of environmental impact into an ecologically interesting ecosystem subject to protection. A 900-metre walkway was built around the lagoon with a picnic area, a fitness park and a jetty. Additionally, the area was converted into a reserve for catch-and-release fishing, where trout is the main species. It uses artificial flies and a spoon lure with one hook. Only one fishing rod per person is allowed. There are houses, fields and some old clay factories in the surroundings of the lagoon.