Stockholm, Sweden

Stockholm, the capital of Sweden, was founded around 1252 by Birger Jarl and spreads across 14 islands where Lake Mälaren meets the Baltic Sea, with roughly 1.65 million residents in the metropolitan area. Gamla Stan, the Old Town, holds the 13th-century Storkyrkan Cathedral, the 608-room Royal Palace completed in 1760, and Mårten Trotzigs Gränd, a narrow street measuring just 90 centimeters wide. The 1628 Vasa warship sank on its maiden voyage and was raised intact in 1961, while Skansen, founded in 1897, is the world's oldest open-air museum. Beyond the city, the Stockholm archipelago of around 30,000 islands fans out into the Baltic.