Carreg Samson is a 5000-year-old Neolithic dolmen located half a mile west of Abercastle. It has a capstone, 4.7 metres by 2.7 metres and 1.0 metre thick. The capstone rests on three of six stones 1.1 to 2.2 metres high.
The whole burial chamber was once covered by a mound of earth or stones and once these were removed stones were used to block the holes in the sides of the tomb so that it could be used as a shelter for sheep.
The site was excavated in 1968 which revealed four additional stone-holes, one having supported a further chamber stone, the others indicating a possible passage leading off to the northwest. Slight traces of a covering cairn were found to the south and it was shown that the monument had been raised over a pit 0.8 metres deep, filled with clay and stones. Finds included a small quantity of burnt bone, pottery, and flints.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.