A few years ago, the Jerusalem Municipality put these cute little loos, WCs, one-person prefabricated Public Toilets around the city. No doubt they had seemed like the perfect solution for areas in which didn't have the space for anything more conventional.
Since they are designed for just one person at a time and handicapped accesible, only one would suffice. Nowadays, there aren't too many left. This one is in the small public plaza on Hillel Street near the Italian Synagogue Museum and the back entrance to Music Square. I was happy to discover it, since there aren't any public toilets in that area at all.
But then I checked it out, following the posted instructions. The door opened easily, too easily, but it no longer locks when you shut it. The mechanism is gone. It was awful. Luckily I was there more for research than actual use. You'd need a "buddy" to guard yourself if you were going to use it for what it was designed.
Too bad; it was nice in theory. If you really need a WC in that part of Jerusalem, either go into one of the restaurants or walk to a different part of the city centre. #20 and #19 aren't too far away.
I hope that this was helpful. If you have any suggestions, please mention in the comments, thanks.