Tapping just the right brick in the wall behind the Leaky Cauldron pub in London ("Three up...two across...") will reveal an archway which is a portal into Diagon Alley, a long cobbled street where is to be found a strange and exciting assortment of shops and restaurants, some of which have tables outside with brightly colored umbrellas. Does Diagon Alley exist in Muggle reality? It would seem so, since Harry heard traffic outside his room in the Leaky Cauldron. Of course, that may be simply the fact that the Leaky Cauldron itself is in Muggle space, but the Alley on the other side of the magic portal is not.
