TIL that Sir David Attenborough is largely responsible for tennis balls being yellow (or green, depending on who you ask).
In 1967, Sir David Attenborough was in charge of BBC2’s coverage of Wimbledon. The event was being televised in color for the first time, and he decided to change the tennis balls from white to yellow for easier visibility when they crossed the white pitch lines. It caught on, and now almost all tennis balls are yellow.