The city of Hannover at River Leine was founded around 1150 and quickly developed to a trading metropolis in northern Germany. It joined the Hanseatic League as early as the 13th. Today the city has more than 500,000 inhabitants and is the capital of the state of Lower Saxony. With the magnificent Herrenhausen Gardens and the large city forest Eilenriede, it is one of the greenest cities in Germany. Due to its central location in Germany and Europe, Hannover is an important business and science location in Germany. Hannover is also known worldwide for its exhibition center, where the EXPO 2000 world exhibition took place in the year 2000.