Suomenlinna Fortress (tel. 09/684-18-80) is an 18th-century fortress in the Baltic's archipelago on seven islands, five of which are interconnected with bridges, that guard the maritime approaches to Helsinki. With their walks and gardens, cafes, restaurants, and old-frame buildings, the islands are one of the most intriguing outings from Helsinki. Originally built in the mid-18th century, when Finland was a part of Sweden, the fortress was named "Sveaborg" by the Swedes and later became known by the Finns and Russians (who assumed control in 1808) as Viapori. After Finland became an independent country, the fortress acquired its present name, Suomenlinna, which means "the fortress of Finland." It served as a working part of the nation's defenses until 1973. A complete visit to this site requires at least 4 hours for a full investigation.
You can take a ferry from Market Square to Suomenlinna year-round beginning at 6:20am daily. The boats run about once an hour, and the last one returns from the island at 1:45am. The round-trip ferry ride costs 2€ ($3.20) for adults and 1€ ($1.60) for children 5 to 15; free for kids 4 and under.
The island has no "streets," but individual attractions are signposted. During the peak summer months (June-Sept), Suomenlinna maintains two information kiosks, one at Market Square (by the departure point for the Suomenlinna ferryboat), and a second on the island itself (near Tykistölahti Bay). The latter kiosk serves as the starting point for guided tours -- offered in English -- of the fortress, with a focus on its military history. Tours are scheduled between June and August, daily at 10:30am and 1pm. From mid-April to May, and from September to early December, they're offered on a limited basis (only Sat-Sun at 1:30pm). They cost 6.50€ ($10) for adults and 3€ ($4.80) for children 5 to 15; free for kids 4 and under. The rest of the year, the guided tours, which must be reserved in advance, are offered on an as-needed basis and priced at around 150€ ($240) for up to 16 participants.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.