KAAABA

There would seem to be difficulties with the whole world becoming moslem. Take the population as being six-odd billions, the average age 65, then about 103 million people need to make the hadj every year if the entire lot are going to get through in their lifetime (as opposed to something like 3 mill p/a at the moment). That means 103 million people are going to have to circle the kaaba three times. The mosque there is reputed to hold 800,000 in the courtyard, but I'm not clear if that's standing or circling. Say 750,000 at a time. Then you'd have to get them in and out every 40 minutes; not easy. the only way I see it as being possible would be for there to be several levels - and even then that wouldn't make the circling much easier. Perhaps if you had a spiral ramp around the kaaba so the lines didn't have to cross? I'd suspect that even then you'd need a moving pavement. And that doesn't allow for anybody going twice.