When it was built, the monumental spa complex dating back to the 2nd century was the second largest of its kind in the whole Roman Empire. It covered an area of 42,000 square metres, the size of six football pitches. The oldest spa complex in the city afforded its guests wellness and relaxation at the very highest level. Guests spent their time in the spa oasis and culture centre, enjoying a swimming pool and various baths, some of them heated. There were also libraries, restaurants, shops and beauty salons for the guests to enjoy.

The floor plan of the thermal baths is based on a North African style in terms of orientation of the swimming pools and bathing rooms. Findings reveal that the baths had rich marble fittings, with niches designed as sea grottos. The complex was in use until the 5th century, when it underwent various construction works and was subsequently used as a quarry. The decline and dismantling of the baths led to the growth of the St Barbara district of Trier from which the baths derive their current name.

A visitor pathway around the complex brings the baths back to life again. There are nine stations showcasing not only the architecture and the magnificent fittings of the complex, but also the bathing process in Roman times based on reconstructions. There are also illustrations of the developments after the ancient period and the current restoration work in the baths.