text: Mannheim is unusual among German cities in that its city centre streets and avenues are laid out in a grid pattern, leading to the city's nickname Quadratestadt (Square City). Within a ring of avenues surrounding the city centre, there are squares, numbered from A1 to U6, instead of street names. At the southern base of that system is Mannheim Palace, one of the largest palace complexes in the world, and the second-largest in Baroque style after Versailles. It was the former home of the Prince-elector of the Electoral Palatinate, and now houses the University of Mannheim, which repeatedly receives top marks in business administration and is sometimes known as the "Harvard of Germany". The Mannheim May Market is the largest regional consumer exhibition of Germany. The civic symbol of Mannheim is the Romanesque Mannheim Water Tower, completed in 1886 and rising to  above the highest point of the art nouveau area Friedrichsplatz. Mannheim is well-known for its inventions, including the automobile, the bicycle, and the tractor, which is why the city is often called the "city of inventions". The city is the starting and finishing point of the Bertha Benz Memorial Route, which follows the tracks of the first long-distance automobile trip in history.