What is Bulgaria's bathing and thermal culture like — and is there anything on the coast?

Bulgaria is a thermal country: official materials cite over 700 mineral springs, and balneology has a long tradition. On the southern coast right by Burgas lie the Burgas Mineral Baths with hyperthermal water (41 to 48 degrees) — home to the historic Aquae Calidae and the modern longevity spa Therma Numera. Pomorie is known for its healing mud from the salt lake. Across the country, Velingrad (the self-styled spa capital of the Balkans, with around 80 springs), Sapareva Banya (Europe's hottest geyser at 103 degrees) and ancient Hisarya with its Roman baths are worth a trip; plus Devin, Bankya, Kyustendil and Pavel Banya. From skiing in winter to thermal bathing year-round the range is wide — addresses and maps in the link directory.