Five mini-roundabouts arranged in a circle, with traffic flowing around the ring clockwise and around each individual mini-roundabout clockwise as well. It sounds impossible until you try it — and then it mostly makes sense, though first-timers tend to brake, stare, and inch forward nervously.
The Magic Roundabout is not a tourist attraction in the traditional sense, but it has genuine cult status among road enthusiasts and has appeared in television programmes about unusual British infrastructure. It's also reasonably effective: traffic moves through it faster than it would through a conventional large roundabout or a set of traffic lights. Worth a drive-through or a walk over to observe, particularly at busy times.