Once a year in May the Port of Hamburg, the "door to the world," is truly tops: About 1.5 million people every year celebrate the Hamburg Port Birthday - the greatest harbour festival in the world - on the nearly four kilometre-long "Harbour Mile" along the Elbe between the HafenCity and the Övelgönne Museum Harbour. Special highlights include the breathtaking fireworks display, ship launches and parades, and the unique tugboat ballet.The Port of Hamburg and its birthday have a long tradition. Since Kaiser Friedrich Barbarossa granted citizens of Hamburg a charter on 07 May 1189, which guaranteed exemption from duty for ships on the Elbe from the city to the North Sea, Hamburgers have drunk to the birthday of their harbour. The PORT BIRTHDAY HAMBURG is officially celebrated, but only for a little over a quarter of a century. Since that time, the Port Birthday has grown and is a popular attraction for visitors from near and far.The maritime experience begins traditionally with the international ecumenical mass in the main church of St. Michaelis at Friday noon. It is followed by the official opening on the museum ship Rickmer Rickmers, which rings in the great entrance parade, usually consisting of more than 300 sailing vessels every year.