On the map of Vienna's urban centre, there is a four-kilometer circle of boulevards called Ringstrasse, or Ringstrae. The road around the city is 57 meters wide, along which are tall trees and lawns. Along the magnificent broad Boulevard around the city, there are some of Vienna's most important historic sites, including world-famous buildings and magnificent buildings, as well as monuments and parks. There are 23 districts in Vienna. The area numbered 1 around City Avenue is Innere Stadt. The areas outside are numbered clockwise from inside to outside. Nine sections of the Ring City Avenue, named after it, are like a green velvet belt decorated with Vienna.