In this fascinating discussion, Physicist Dr Tony Heyes explains the background and importance of the 1960s scientific revolution which became known as plate tectonics. He describes the roles played by German researcher Alfred Wegener and English geophysicist Frederick Vine in realising that it wasn't just a coincidence that the West coast of Africa and the East coast of South America have a similar shape and look like they might once have neatly fit together. Tony also explains geomagnetic pole reversals and the long-term cycles which influence climate and cause ice ages.