During World War II, Prof. Dr J.H. Oort, the famous Dutch astronomer and discoverer of the origin of our comets, was living in the countryside of The Netherlands. At that time, it was an occupied country. He decided one day to ride his bicycle to visit the observatory at Leiden University, which in fact had been closed for some time. Halfway on this 120 km trip to Leiden, which is near the North Sea coast of The Netherlands, he got a flat tyre and was forced to interrupt his trip at the residence of one of his promising students. With this student, the future Prof. Dr. H.C. van de Hulst, he discussed potential new means, in addition to the well-known optical methods, to observe gaseous clouds in the galaxy. It was probably the first time that professional astronomers discussed the possibilities of radio astronomy. In the following postwar years, radio astronomy in Australia, England, and the United States led to many fascinating discoveries. The article outlines developments at Kootwijk, in the center of The Netherlands, and throughout the world.