Visiting the thermae with their heated rooms and pools was a set part of the ancient Roman lifestyle. Not wanting to forgo the luxuries of Rome, the Romans built public baths even in cities far distant from the capital – Carnuntum was no exception.
The biggest challenge during the building of the thermal baths by hand was to reconstruct the Roman underfloor heating system (hypocaust). The reconstruction of the water supply for the pools also proved to be extremely complex. The result is the only Roman baths worldwide that were built to be fully functional at their original site using ancient construction methods. They have been heated ever since by this Roman underfloor heating system.
The basilica thermarum was the central hall where people gathered together in the Roman baths. The wing behind it containing the actual thermal baths was precisely laid out with a series of rooms at different temperatures - fridiarium, tepidarium, and caldarium.