This is the least interesting part of what was once the largest system of fortifications in the world, and in any case you can't get in to see it.
You can only get in to see it on Sundays.
mnli hypothesis: You can only get in to see it on Sundays. premise: This is the least interesting part of what was once the largest system of fortifications in the world, and in any case you can't get in to see it.