In 1968, Ernest Walton participated in the Lindau Meetings for the first time. He could have accepted the invitation much earlier, but probably found it difficult to escape from his professorial duties in Dublin before retirement. He only gave one lecture, the present one, but came back to the physics meetings in 1971 and 1973 (in 1973, the meeting succession changed from medicine-chemistry-physics to medicine-physics-chemistry). In his lecture, Walton gives an engaging account of his work with Ernest Rutherford in Cambridge, work that culminated in the construction of a high-tension accelerator together with John Cockcroft. The idea of the construction of this so-called Cockcroft-Walton accelerator, emanated with the creative theoretician George Gamow. Gamow, who never received a Nobel Prize, had proposed that the alpha particle decay of atomic nuclei took place through quantum mechanical tunneling. If so, there would also be a possibility for protons to enter atomic nuclei even if the proton energy was not large enough to overcome the repulsive Coulomb barrier. In 1930-32, Walton and Cockcroft constructed the accelerator and showed that protons could enter light nuclei and thus transform them from one place in the periodic table to another. The nuclear isotopes thus produced became radioactive, which was of great interest for their use, e.g., as tracers. George de Hevesy received the 1943 Nobel Prize in Chemistry for his work using these kinds of light (non-toxic) radioactive isotopes. Walton and Cockcroft became the first to artificially induce nuclear reactions and transmute elements, an activity that became of even larger interest after the discovery of the neutron by James Chadwick in 1932. This eventually led to the discovery of nuclear fission and nuclear power. Walton’s co-Laureate Cockcroft lectured three times in Lindau, all three times on nuclear power.