Where were you when Kennedy was shot? Too young? Where were you when the Berlin Wall came down? Or when Margaret Thatcher resigned* All critical, epoch- making events, if you're old enough.
But harder to define are the equally important birding events. Where were you when you when Hen Harriers were reduced to one breeding pair in England? Where were you when the Scottish Government's wildlife policies were shown to be a sham. Or when the self- styled Greenest government ever...