Frankfurt is the largest city in the German state of Hesse and the fifth largest city in Germany. It is the largest financial center of Germany, as well as in continental Europe. Frankfurt is also one of the richest cities in the European Union, and has a population of approximately 648,325,000 people. Frankfurt is home to cathedrals dating back to the 14th century, an old Opera House, several modern buildings and skyscrapers, and is one of the host cities for the 2006 FIFA World Cup in Germany. Many large trade fairs take place in Frankfurt each year, including the Frankfurt Motor Show and the Frankfurt Book Fair, both of which draw more than 100,000 attendees. Other important special interest fairs including the LinuxWorld Conference & Expo or Musikmesse Frankfurt. The southern part of the city contains the Frankfurt City Forest Germany's largest urban forest.