text: When World War I broke out in 1914, Mannheim's industrial plants played a key role in Germany's war economy. This contributed to the fact that, on 27 May 1915, Ludwigshafen was the world's first civilian settlement behind the battle lines to be bombed from the air. French aircraft attacked the BASF plants, thereby killing twelve people. The precedent was set for this attack by Germany's repeated air raids against British civilian populations throughout southeastern Britain during the first half of 1915.
  When Germany lost the war in 1918, according to the peace terms, the left bank of the Rhine was occupied by French troops. The French occupation lasted until 1930, and some of Ludwigshafen's most elegant houses were erected for the officers of the French garrison.
  Inter-war period
  After the First World War, the Heinrich Lanz Company built the Bulldog, an advanced tractor, powered by heavy oil. As a result of the invention of the pre-combustion chamber by Prosper L'Orange, Benz & Cie. developed the world's first compact diesel-powered car at its motor works in Mannheim in 1923. In 1922, the Grosskraftwerk Mannheim (Mannheim large power station) was opened. By 1930, the city, along with its sister city of Ludwigshafen, which had developed out of the old Mannheim Rheinschanze, had a population of 385,000.