Diagon Alley at Warner Bros. Studio Tour London

Diagon Alley (Harry Potter) is a fictional high street located in London. It is accessible to the wizarding world, to which it is something of an economic hub, but hidden from Muggles (non-magical people). However, Muggles are allowed access to it if they need to accompany their Muggle-born magical children. If a wizard or witch needs something, chances are that it can be found in Diagon Alley.

http://www.wbstudiotour.co.uk/