If you have half an hour to spare, this Veritasium breakdown of how fibre came to replace copper is well worth your time. In the 1960s, copper wiring was hitting its physical limits, yet early glass fibres lost far too much light to be useful over any real distance. It took the relentless dedication of pioneers like Charles Kao whose own boss dismissed the idea as a “wild goose chase” and a small team of scientists at Corning to pull off one of the greatest materials-engineering breakthroughs in history and lay the foundation for the modern internet.