Stockholm the capital and the largest city of Sweden is built on 14 islands and has many waterways passing thru it. Because you are never far from the water the city is often called "The Venice of the North".
The city is protected from the open seas by "Skärgården", an archipelago consisting of 24,000 islands, islets, and skerries. Stockholm is very environmentally friendly, the air is significantly cleaner then in many other city's and during the summer it is actually possible to swim and fish in the middle of the town.
The Old Town "Gamla Stan" located in the center of the city is the island where Stockholm began in the 13th century. It is a district of winding narrow alleys and old buildings which includes the Royal Palace. Today the city have grown to a population of over 1 million inhabitants and every year on December 10 the Nobel Prizes are awarded here.
Look at maps of Stockholm City