Helsinki

Helsinki is the natural stop on a Europe to Asia routing through Finland, and the commuter train makes it painless: the P and I trains reach Helsinki Central Station in about 30 minutes, on an ordinary regional ticket. The center is small enough to cover on foot. Walk from the station to Senate Square and the white Lutheran cathedral, then down to the Market Square on the harbor, where ferries leave for the island fortress of Suomenlinna if you have a few spare hours. In winter, daylight is short, so an early-afternoon window shows the city at its best.