Turku

Finland's oldest city stands at the mouth of the Aura River on the southwest coast, its medieval origins visible in the riverside cathedral founded in the 13th century and the well-preserved Turku Castle at the river's mouth. The city served as Finland's capital until 1812, and its archipelago — the densest concentration of islands in the world — stretches south into the Baltic. A chain ferry service connects the island chain toward the Åland Islands.