Suomenlinna is a sea fortress located in Helsinki, Finland. It was built on six islands and is a UNESCO World Heritage Site.

The history of Suomenlinna dates back to the 18th century when it was built by the Swedish as a defense against Russian expansionism. The fortress was originally named Sveaborg, or "Swedish Castle," but was later renamed Suomenlinna, or "Castle of Finland," after Finland became a part of the Russian Empire in 1808.

Throughout its history, Suomenlinna has played a significant role in the defense of Helsinki and Finland. It was used as a military base and as a prison and even served as the capital of Finland for a brief period during the Finnish Civil War.

Today, Suomenlinna is a popular tourist attraction, with more than 900,000 visitors each year. It is home to several museums, cultural attractions, and a thriving residential community. Visitors can explore the fortress's tunnels and bastions, or take a boat tour around the islands.

One of the most popular attractions at Suomenlinna is the Maritime Museum, which showcases the history of the fortress and its role in Finnish naval history. The museum features exhibits on naval warfare and shipbuilding, as well as a collection of ship models and naval uniforms.

Another popular attraction at Suomenlinna is the Toy Museum, which houses a collection of more than 10,000 toys, including dolls, teddy bears, and other childhood favorites. The museum also features interactive exhibits, where visitors can try their hand at traditional Finnish games and crafts.

In addition to its museums, Suomenlinna also offers a variety of outdoor activities, such as hiking and picnicking. There are several park-like areas on the islands, as well as a public beach and several playgrounds.

In short, Suomenlinna is a unique and fascinating destination, offering a glimpse into Finland's rich history and cultural heritage. Whether you're interested in military history, toy collecting, or just want to spend a day outdoors, there's something for everyone at Suomenlinna.

If you plan to visit Suomenlinna, plan at least 2 hours to visit the place, and go when the Sun is up because the views are amazing, the ferry is only about 10 minutes and the ticket to go there can be bought using HSL application.