With nearly 700 pieces, Hogwarts Castle from the Harry Potter Lego sets range is one of the largest sets. It will certainly keep you busy for a fair few hours building all the rooms, halls, towers and the like. When you have finished though you will have a stunning replica of the great Harry Potter castle. The rooms included in the instructions are the dining hall, Owlery, library and the hall outside the Gryffindor quarters, but any number of other rooms or scenes could be made instead. Once built the castle has an abundance of fun features including hidden staircases and creepy trap doors. It is also amazingly tall with arches, multiple towers and grated windows. If you want to build a scene that will really bring Harry Potter to life, this is the set for you. It is quite hard to find though so check on Ebay for a price that is not too excessive.