 This experience was so profound that a decade later, in 1991, he wanted to "write a story about the people guarding the end of the world", and ultimately "the things that come out of the [fictional] north are a good deal more terrifying than Scotsmen or Picts".Martin adjusted the size, length, and magical nature of the Wall for genre demands; Jon Snow's chapters describe it as approximately long and high in general, rising up to a perceived in spots due to huge foundation blocks.The top is wide enough for a dozen mounted knights to ride abreast (approximately 30 ft or 10 m), while the base is so thick that the Wall's gates are more like tunnels through the ice.