A caldarium is a type of room found in ancient Roman baths, specifically designed for hot bathing. It was typically heated by a system called a hypocaust, where hot air circulated beneath the floor and through the walls. The temperature in a caldarium could reach up to 40-50 degrees Celsius, providing a relaxing environment for bathers. In addition to its heat, the caldarium often featured large, circular pools filled with hot water. Bathers would use this space to cleanse themselves and socialize. The caldarium was an essential part of the Roman bathing culture, which emphasized hygiene and relaxation in communal settings.