You may recall Alnwick Castle as the spot where Harry took his first ride on a broomstick. In real life, it has been the home of the Percys, earls and dukes of Northumberland, since the 1300s. Read more.
The impressive single-track structure makes cameos in the Harry Potter films but most memorably in No. 3, when the dementors stop the train and give Harry some trouble. Read more.