The Battle of Bomarsund was fought between the Russian defenses at Bomarsund and an Anglo-French task force. After a week of fighting the British stormed the "remaining" fort and at the end of the battle the fort of Bomarsund was destroyed.
Three hundred Finnish grenadiers defending the fortress were captured and taken to Lewes Prison in the United Kingdom. They were later allowed to return to Finland, and they returned with a song telling about their battle and imprisonment, called the War of Åland
Nowadays there is a small museum where you can get more information about this historic place.
Follow the cache and you will easy find this museum.
No fee for visiting museum is required, but please check tourist information center for working hours.
On our bicycle trip, we spent three days on Prasto camping which is near Bomarsund. All these three evenings we went to Bomarsund where you will find significant view. It is also recomended to have a picnic near museum and wait for sunset.
Cache is a small size rubber box. Coordinates provided are quite precisely, so it shouldn't be so hard to find it.
Inside you will find a log book, pencil and FTF - lithuanian armlet. This is our present from Lithuania :)
Especially thanks to maha5! She found this friend in Aland who agreed to take care of cache in case we are not local there.