Barbara Baths
Trier, Germany
The Barbara Baths (German: Barbarathermen) are a large Roman bath complex in Augusta Treverorum, modern-day Trier, Germany. Stretching over 42,000 square meters, it is the largest Roman bath north of the Alps. Along with other sites in Trier, the bath complex was designated a UNESCO World Heritage Site in 1986 as part of the Roman Monuments, Cathedral of St. Peter and Church of Our Lady in Trier site, because of its historical importance and sprawling architecture.
Archaeological site data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).