Frigidarium

A frigidarium is a large cold pool at the Roman baths. It would be entered after the caldarium and the tepidarium, which were used to open the pores of the skin. The cold water would close the pores. There would be a small pool of cold water or sometimes a large swimming pool (though this, differently from the piscina natatoria, was usually covered). The water could be also kept cold by using snow.