Game Of Thrones: The Long Night, Explained

There was a period of time in Westeros that saw darkness completely blanket the skies. This was a terrible time for the living as it saw the rise of a nearly demonic race of monsters that were nigh impossible to kill. At the time, the living called these monsters the Others, but audiences know them better as White Walkers, the icy zombie-like creatures that reside in the far north of Westeros beyond the great wall. The Long Night lasted for a generation.