Perched on a harbor rock, the Little Mermaid welcomes visitors to Copenhagen, a lively Danish capital famed for happiness, good food, free education and healthcare, and a 37-hour work week. The city blends modern architecture, world-class museums, charming canals, and Old Town streets in the world's oldest kingdom, plus 15 Michelin-starred restaurants and Strøget, the world's longest pedestrian shopping street.

Travemünde, on Germany's Baltic coast at the mouth of the Trave, is a nostalgic seaside resort with striped beach chairs, wide sands, and a promenade of cafés and ice cream stalls. Nearby, the 1911 four-masted barque Passat serves as a floating museum. It also gateways to Lübeck, 30 minutes inland: a UNESCO-listed Hanseatic city of red-brick Gothic gables, merchant houses, medieval warehouses, the Holstentor gate, and famed marzipan shops.

Karlskrona blends naval heritage, a friendly feel, and easy access to outdoor adventures. In 1680, Karl XI chose the southern archipelago as Sweden's naval base. Trossö's 17th-century grid is still the Baroque heart of the city, now spread over 33 islands. From the town square and its landmarks to the Naval Port, Naval Museum, and Björkholmen, many sights are walkable. The old fish market is now the gateway to the archipelago.

Helsinki, Finland's capital and largest city, is a cultural hub with museums, galleries and theaters, including the Ateneum's nearly 30,000 works of art. Rebuilt under Russian rule in the 19th century, its neoclassical center features Senate Square, boulevards, parks and grand architecture. Market Square offers local crafts and salmon soup. Nearby Suomenlinna, a UNESCO fortress island reached by ferry, has museums and parkland.

Tallinn's UNESCO-listed Old Town is one of Europe's best-preserved medieval cities, with 13th-16th century churches, homes, and public buildings from Hanseatic merchants. Highlights include St. Olaf's Church, Alexander Nevsky Cathedral, Toompea Castle, and the Gothic town hall. Finish with a stroll in Kadriorg Park and its art museum in an 18th-century Russian palace.

The Åland Islands are a spectacular Finnish archipelago of 6,500+ islands. Mariehamn, the capital, is a picturesque, laid-back town of 11,000 with a strong maritime culture. Once home to the world's largest fleet of oceanic sailing ships, it offers the Maritime Quarter, the award-winning Maritime Museum, and the Pommern, one of the world's last merchant sailing ships. Nearby are the Bomarsund Fortress ruins and Kastelholm Castle, reflecting the Swedish and Russian eras.

Stockholm's approach through the archipelago is breathtaking. Spread over 14 islands and crossed by 57 bridges, it's called "the city that floats on water." Visit Djurgården for the Vasa Museum and the Skansen open-air museum, wander Gamla Stan's medieval streets, and see nearby UNESCO sites: Birka, Skogskyrkogården, and Drottningholm Palace, home to the royal family since 1662.