Museum of the Moon at Colchester Castle

Luke Jerram's touring Moon, lit from within using real NASA imagery, is an easy thing to describe and a much stranger thing to stand under — it hangs at eye level in the castle's vaulted hall, so children and wheelchair users get exactly the same close-up view as anyone else.

Worth catching before it comes down at the end of October; the castle itself, the largest Norman keep in Europe, is reason enough to go regardless.