Cruises that travel the Baltic Sea can carry their passengers from the wonders of St. Petersburg’s Hermitage Museum to the stunning fjords of Norway. Winter cruises expose travelers to the icy beauty of Europe’s north (as well as its cozy holiday markets) but summer cruises—the most popular time of year for Baltic tours—reward passengers with a more temperate climate, lush meadows bursting with flowers, and nearly 24 hours of daylight.