The biggest discovery of the 20th century happened on March 3rd 1938, when the biggest oil reserve was found in the arabian desert enabling WW2 with annexation of Austria 10 days later on March 12th 1938, first oil export tanker leaving Saudi Arabia on April 30th 1939, Ibn Al Saud delegation in Germany on June 17th 1939, WW2 September 1st 1939.