12 Fortified Port Cities Where History Meets the Ocean Waves

11. Suomenlinna (Helsinki), Finland: Gibraltar of the North

Built by Sweden in the mid-18th century on a cluster of islands guarding Helsinki's harbor, Suomenlinna (Sveaborg) is a unique maritime fortress, often dubbed the "Gibraltar of the North." Its ingenious design, adapting to the archipelago's terrain with irregular bastions and extensive tunnels, made it a formidable naval base. Now a UNESCO World Heritage site, it’s a living part of Helsinki, offering museums, parks, and a powerful sense of maritime history where Baltic winds sweep across its weathered ramparts and cannons.