Imagine you and your friends playing a game of capture the flag. Now, imagine that instead of a flag, the thing you're trying to capture is an entire island! That's kind of what happened at the Battle of Suomenlinna.
Suomenlinna (pronounced soo-men-lin-na) is an island fortress in Finland that was built a really long time ago to protect the country from invaders. Back when Finland was ruled by Sweden, the Swedes built the fortress to keep other countries from trying to take over Finland. But in 1808, Finland was no longer part of Sweden and had become a country of its own. This is when the battle happened.
In the Battle of Suomenlinna, the Russians wanted to take over Finland, including the island fortress. The people who were defending the fortress were Finnish troops and Swedish troops. The battle started in February, when the Russians first attacked the island. The Finnish and Swedish troops tried their best to protect the fortress, but the Russians were really strong and had a lot of soldiers. The battle went on for several months.
The fighting was really intense, and both sides had a lot of casualties (people who were injured or killed in battle). The people who were defending the fortress were running out of supplies, like food and weapons. Eventually, they had to surrender to the Russians.
The Battle of Suomenlinna was a really important moment in Finnish history because it showed how brave and determined the Finnish and Swedish troops were. Even though they didn't win the battle, they never gave up and fought as hard as they could to protect their country. Today, the island fortress is still there as a reminder of this historic event.