Built by Vauban between 1667 and 1672, the purpose of Citadel of Arras was to protect the city from the attacks (Spanish troops coming from the Netherlands). It has been nicknamed La belle inutile (the beautiful useless one) by residents as it has never been directly involved in heavy fighting and didn't keep the Germans form occupying the city in either Word War. Since 7 July 2008 it is part of the UNESCO World Heritage Sites Fortifications of Vauban which includes eleven other fortifications. Within the citadel on the side of La Place de Manœuvre a small Baroque-style chapel was built. Outside, Le Mur des Fusillés (the wall of the people executed by a firing squad) pays tribute to the 218 members of the French Resistance shot in the citadel's ditch during World War II.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.