The Altfriesisches Haus in Keitum is one of the best small museums for understanding Sylt before beach tourism and expensive second homes took over the island's image. The thatched house preserves rooms, furniture, tiles, and domestic details from old Frisian island life, making it more intimate than a general local-history display.
Keitum itself is part of the appeal, with lanes of thatched houses and a quieter mood than Westerland. Visit the museum as part of a slow walk through the village, then continue to the nearby churchyard, coast, and older captain's houses.