Mannheim, Germany

Mannheim sits in Baden-Württemberg at the confluence of the Rhine and Neckar rivers, where roughly 315,000 residents live within a 1606 chequerboard street grid that ranks among the earliest planned cities in Europe. Its addresses run from A1 to U9 instead of bearing street names, an unusual system that still guides visitors today. The 1720 Mannheim Palace stretches 450 meters wide with 1,500 rooms and housed the Electors Palatine, while the Mannheim National Theatre premiered Schiller's The Robbers in 1778. Carl Benz built the first automobile here in 1885, and the 1955 Bertha Benz Memorial Route traces the long-distance drive his wife took three years later.