I think there are more roundabouts per square mile in MK than any major town/city in Europe, though I can't find the source which proves that. I remember it once being described as the "Mecca of roundabouts". There are 300 roundabouts in Milton Keynes, which is effectively one roundabout per 600 people, and one roundabout every 296 square metres. Swindon has the best roundabout in the world, though: It means you can effectively go around the roundabout the wrong way. Epic.