The well-preserved Drena Castle ruins stands on the rock overlooking the deep gorge of the Salagoni River. Built in the 12th century, Drena was probably erected over a prehistoric village. During the Middle Ages, the castle became an important stronghold to control the road connecting Trento and Lake Garda. Unassailable from the flames, the castle is defended by two rows of walls and has been constructed in a dominating position over a gorge - rendering it impregnable to the techniques in use at the time. The castle is mostly Romanesque, but includes a number of Gothic features and 16th century structures.
Frequently contended, in 1703 Drena castle was destroyed by French troops led by General Vendome as well as practically all the castles in the area.
Recently refurbished, Castel Drena can be visited throughout the year, and uses to host numerous cultural events, as well as a permanent exhibition. Overlooking the complex is the 25 metres high fourteenth-century tower, the top of which affords a view over the evocative Marocche stone quarry.
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.