The Lutheran church of Burtnieki is located on the Eastern bank of the lake. The first church was built there in 1234. It was a Catholic church, built from wood. It burned down and was replaced by a stone wall church between 1283-1287. It was destroyed in 1654, during the Polish-Russian War.
The current church was built in 1688. Near the church is located a minister estate building complex, renovated in 1992. The estate building has been defined as a protected architectural monument.References:
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.