Ever wondered why tennis balls are yellow? Believe it or not, tennis balls weren't always this bright fluorescent colour. For decades, players used white tennis balls without any issues, until colour television changed everything. In the late 1960s, broadcasters discovered that white tennis balls were surprisingly difficult for viewers to follow on colour TV screens. One person who noticed this issue was Sir David Attenborough, who was working in television long before becoming the world-famous natural history presenter we know today. And voila history was created! Watch the video to know the whole story!