One of the most important harbours in Europe and the world, Hamburg takes great pride in its mercantile background, which built the city's wealth in the past centuries. From 1241 on, it was member of the Hanseatic League, a medieval trade monopoly across Northern Europe. In the 19th and beginning of the 20th century, millions left Europe on their way to the new world through the Hamburg harbour. Today, the harbour ranks second in Europe and eleventh world-wide. Consequently, one of Hamburg's tag lines is "The Gateway to the World". There are a number of small beaches on the North side of the Elbe river between Övelgönne and Blankenese. Even though not common, it is safe to swim in the Elbe there (if you don't swim out too far). You may have a barbecue there in the evenings, as long as you bring a grill and clean up after yourself. Hamburg publishes a thick, detailed booklet of local museums called "Museumswelt Hamburg". You can find the Museumswelt Hamburg at the information desk at any of the museums. Hamburg also has a busy night-life, many art galleries, theatres and places to listen to live music.