Muhu Museum is situated in the historical Koguva village. The museum exhibits the old village school from the 19th century, traditional peasant culture, local school history and traditional textiles. The heart of the museum is Tooma farmstead which is a representative example of Muhu farm architecture. In its outbuildings old agricultural and fishing equipment is exhibited. In the main building, visitors find a small introduction to Juhan Smuul’s life and work. Juhan Smuul was a poet, drama and prose writer, and remarkable author of non-fiction.
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.