Britain's second-highest mountain, where experienced climbers have reported the same thing since the early twentieth century: a sense of presence, the sound of footsteps following in mist, and a panic that drives them down. Professor Norman Collie described his own experience publicly in 1925, at real risk to his reputation. The thing is called the Big Grey Man; an explanation involving echoes and the Brocken spectre exists, and does not convince those it has happened to.