Bulgarian archaeologists find Roman-era frigidarium in Bourgas | The Sofia Globe:
Archaeological digs carried out this summer on the site of the Roman-era public baths in the Bulgarian city of Bourgas have found the first frigidarium – a cold-water pool – that was part of the the Aqua Calidae baths.
The digs are part of a conservation and restoration project by the Bourgas municipality, meant to turn the Aqua Calidae – Thermopolis site, which housed public baths during the Roman, Byzantine and Ottoman eras, into a tourist attraction, the city hall said.
Found at a depth of about 4.6 metres underground, it has a length of 6.8 metres and is 6.4 metres wide. It had a brick floor that in some place did not stand the test of time and architectural features that have led archaeologists to believe that it was built in the second century CE, when the first public baths were built on the site by Roman authorities.
A frigidarium was the last pool that bathers would enter in the Roman baths (after the tepidarium and caldarium) and its temperature was kept cold to close skin pores.