Roman heated bath

In the past, Roman heated baths were heated using a series of underground channels where water previously heated by coal or log fire ran.  Via this method they managed to heat the water to the required temperature and the desired humidity level. 

What is different about the roman heated bath with regard to the other types of heated baths lies in the special climatic conditions of humidity and temperature they produce and maintain.  The temperature is 45º C to 55º C and the level of humidity relative to the air 65% -70% RH.  

	Built in Roman bath with ceiling imitating a starlit sky
	View of the Roman bath from outside