the leaky cauldron,

The Leaky Cauldron is a popular wizarding pub in London. It is the entrance to Diagon Alley, and, indirectly Knockturn Alley. It is now owned by Hannah Abbott, who became the landlady, moving in with her husband, Neville Longbottom. To gain access, a witch or wizard must tap the bricks in the wall in a counter-clockwise order. A doorway to Diagon Alley then forms which then re-arranges back to the original wall after the person(s) has walked through.