The Kuursaal — a spa resort pavilion built in 1899 — is the most elegant building in Kuressaare outside the castle. Its white wooden frame, with a wide veranda and ornamental fretwork details, belongs to the tradition of Baltic resort architecture: designed to be airy and sociable, a place where the 19th-century cure-seekers who came for the island's dolomite mud could promenade, listen to music, and take the air. The building has been variously used as a concert hall, a casino, and a restaurant.
The curative properties of Saaremaa's dolomite mud — rich in minerals, slightly warming when applied — attracted visitors from the Russian Empire and later from across the Soviet bloc. The tradition never entirely disappeared, and the town still has several spa hotels offering mud treatments and seawater baths. The Kuursaal sits just south of the castle park, its faded elegance worth a look even if you are not stopping.