Also known as the Ranjit Institute of Poly-Radio Therapy, the Solarium was built by Jam Shri Ranjitsinhji during his rule by bringing in an expert from France. This slowly revolving tower provides full daylong sunlight for the treatment of skin diseases. With the destruction of two similar solaria in France during World War II, this is probably now the only one of its kind in the world, and certainly in Asia. It is open to visitors after working hours.