The baths (thermae) were designed along a central axis: the caldarium or hot bath; a smaller area for the tepidarium or warm bath; the basilica, which held the frigidarium or cold bath; and the natatio, an open-air bathing pool. Symmetrically arranged on either side of the baths were rooms for changing, massage, depilation, and medicinal use. From the changing rooms (apodyteria), one would go to the gymnasia (palaestrae) to exercise and from there to a sauna (laconica) to induce an even greater sweat. Then the bather passed to the caldarium, after which he scraped his skin clean with a strigil, and to the tepidarium for a cooler bath and, finally, to the frigidarium for a bracing plunge in a cold bath, which was the regimen recommended by Galen, himself.