My understanding is that it's more hyperbolic than that. There are gates around Jerusalem called "Eye of the Needle" (St Alexander Nevskys Church for instance, its supposedly the location of a 1st century city wall) and a man can barely fit through these himself.
I could be totally wrong, of course. Maybe they started naming holes in dilapidated walls that to bring tourists/pilgrims.
Did a quick google for pic examples; https://patmcinerney.wordpress.com/2014/06/30/the-church-of-...