Stockholm is often referred to as the Venice of the North. Water is everywhere, and around 30,000 islands lie in Stockholm’s wondrous archipelago (skärgården). Distinctive red and yellow timber summerhouses occupy some islands while others remain totally unspoiled. A trip on the water, either in and around the city or to one of the islands, should be top on your list. Many tours include lunch or dinner and all give a unique vantage point of the city. Hop-on hop-off options are available too. When downtown, the distinctive Stromma boats are impossible to miss.
Official site: http://www.stromma.se/stockholm/