Home to some of the most magnificent forests in northern Türkiye, Bolu is renowned not only for its spectacular lakes and natural landscapes but also for its remarkable geothermal resources, making it one of the country's leading health tourism destinations. With a thermal spa tradition dating back to the Roman period nearly 2,000 years ago, Bolu's healing waters were later praised by the celebrated 17th-century Ottoman traveller Evliya Çelebi in his Seyahatname (Book of Travels). Today, the city combines this centuries-old thermal heritage with modern expertise in physical medicine and rehabilitation.
Bolu's geothermal wealth is reflected in the diversity of its thermal springs, each characterised by distinctive hydrogeochemical properties. Located just outside the city centre, Karacasu is known for its natural spring temperatures of 42–44°C, allowing its thermo-mineral waters to be utilised while preserving their natural mineral composition. Mudurnu Sarot, with spring temperatures of around 66°C, is distinguished by its sulphate-rich waters, traditionally known as acı sular ("bitter waters"), while the thermal waters of Mudurnu Babas and Seben Pavlu, where temperatures reach approximately 78°C, are also used in drinking cure programmes. Göynük Çatak, characterised by its calcium bicarbonate-rich waters, is used in balneotherapy as a complementary therapy, particularly for rheumatic and musculoskeletal conditions.
Scientific studies indicate that Bolu's mineral-rich thermal waters are used as complementary therapies in balneological treatments, particularly for rheumatic conditions, musculoskeletal disorders and physical rehabilitation. Combined with modern healthcare facilities, vast forest landscapes and exceptionally clean air, Bolu offers visitors an inspiring destination where thermal heritage, nature and wellbeing come together to support both rehabilitation and relaxation.