Thermalism has marked Europe from ancient times to the present day. The most well-known sites were built during the 19th century, when a wide range of new medical and health treatments were developed. The prestigious political and cultural elite travelling to Europe’s spas, creating centres of cultural exchange in numerous cities, may be said to have launched health tourism and even modern tourism as we know it. These celebrities made the reputation of these resorts and gave birth to a real trend, the development of prestigious hotels and a variety of leisure activities, ranging from the first casinos to musical theatres, to covered promenades and landscaped gardens for the entertainment of fashionable tourists. This is the story, but also the shared heritage and memory that the European Historical Thermal Towns Association (EHTTA) decided to promote and valorise when inaugurating a European cultural route.