The Baños de Elguea (Elguea Thermal Center), about five kilometers northwest of Corralillo and 135 kilometers northwest of Santa Clara [1], is supplied by hypothermal (up to 50°C) springs good for treating rheumatism, skin ailments, and respiratory problems. It has swimming pools, a marching tank, mud baths, gym, solarium, massage rooms, and more. Facilities are crude and, at last visit, deteriorated.
Links:
[1] http://www.moon.com/destinations/cuba/cienfuegos-and-villa-clara-provinces/santa-clara