Cruising the Baltic Sea

The Baltic Sea, tucked between mainland Europe and the Scandinavian peninsula, is a chic summer cruising destination, loaded with history, beauty, ethnic cuisines and fjords. Cruise ships that sail here make calls in the capitals of northern Europe, which means you'll be able to add to the stamps in your passport and sample several cultures in one go. So skip the Caribbean and embark from Copenhagen or London to a land of festive music and really, really tall people. Here's where you're headed.

Copenhagen: You don't have to drink a Carlsberg, but you'll want to toast something as you start (or finish) your cruise in Europe's greenest capital. The Danes were touting environmental awareness long before it became trendy, resulting in a city packed with pedestrian walkways and meticulously maintained parks. It's also one of the continent's easiest cities to absorb on foot, with miles of shopping and dining, spires and towers, including the home of Europe's oldest monarchy, where the Royal Guard changes daily at noon. Crystal Cruises offers pre- and post-cruise tours throughout the city on the Baltic Sea, including a visit to the Little Mermaid, a statue inspired by the Hans Christian Andersen story—a classic photo op.

St. Petersburg: Russian czar Peter the Great imagined his eponymous city as a "Window on the west," where his nation would build a cultural, industrial and art showcase that varied wildly from his land's then-backwards ways. Now, as in the 1700s, Peter's city is a success: Italian inspiration mixed with Russian materials creates a unique architectural landscape, with numerous golden domes and shades of green and coral. If Russian luxury is on the docket, opt to travel with Seabourn Cruise Line; its customer service will make the visa-free visit to St. Petersburg (though there's still plenty of paperwork involved), run smoothly, allowing for an early morning trip to the Hermitage—before it becomes packed with land-locked tourists—and an evening performance at one of Russia's finest dance or theater houses.

Helsinki: It's in Scandinavia, but Helsinki's proximity to Russia affords this peninsula city a blend of cultural and ethnic influences. Architecture aficionados will relish the innovative structures that pepper downtown, a symbol of the country's bent toward modern technology (after all, the headquarters of Nokia are just down the way in Espoo). Traveling with Regent Seven Seas Cruises will give you the opportunity to shop the hundreds of outdoor vendors at Kauppatori Market for hand-woven Finnish rugs, glass products and anything you could concoct from reindeer skin, and explore the beautiful historical buildings that abut the square. Perhaps you'd rather stroll through the Esplanade and Stockmann's, Europe's largest department store. Walk along the water—there's plenty of it in this port of call—to take in the bustle and make your way to Upenski Cathedral. It's hard to miss with its golden dome glinting in the sun—and you won't forget the view from high atop the city.

Tallinn: This thousand-year-old Estonian town is the best preserved in Europe, with cobblestone streets and tiny medieval houses in Old Town, an area that has survived Viking attacks, crusades and the Iron Curtain. If you're feeling energetic, join Celebrity Cruise for a countryside cycling tour of Kakumäe. Visit St. Nicholas church—dating to the 13th century—or go even older: The Dominican Monastery in town dates to 1246, and houses the oldest stones in Estonia. Work up an appetite for the unique (if not always delicious) cuisine of Estonia by walking its walled, old city and climbing the narrow streets, as live performers gather in the squares to perform classical and folk music for your benefit.