Hogwarts School serves as the setting for most of the "Harry Potter" series. Students attend Hogwarts for seven years. A Hogwarts year begins in September and runs three terms: September to Christmas, January to Easter, and Easter to June. At the end of a student's fifth year, he must take the Ordinary Wizarding Level (O.W.L.) examination, and at the end of his fifth, he must complete the Nastily Exhausting Wizarding Test (N.E.W.T.). These exams roughly corresponded to the O-Level and A-Level examinations in Britain's actual secondary education system.
Four famous wizards and witches established Hogwarts. Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw and Salazar Slytherin founded four "houses" at the school, which they named after themselves. To be sorted into a given house, a student must possess the qualities most esteemed by the house's founder. Godric Gryffindor greatly valued courage while Helga Hufflepuff cherished hard work. Rowena Ravenclaw required intelligence of her students and Salazar Slytherin asked only that they be ambitious. The founders charged a magical hat that belonged to Gryffindor with the task of sorting students; this hat is known as the Sorting Hat. In "Harry Potter and the Philosopher's Stone," the Sorting Hat places Harry Potter and his friends Ron and Hermione in Gryffindor House.
The novels describe Hogwarts as a magical castle located somewhere in the Scottish countryside. Only a wizard or witch can see Hogwarts; to non-magical individuals, it is invisible. A large lake sits to the south of the castle and a dangerous wood, appropriately named the Forbidden Forest, sits just beyond the school grounds. Since Hogwarts is magical, the layout of the castle, including the location of rooms and staircases, tends to change unexpectedly. The castle is home to numerous magical creatures and beings, including elfs, ghosts and talking portraits.
In "Harry Potter and the Deathly Hallows," the final novel in the series, Hogwarts serves as the setting for a battle between Harry Potter and his nemesis, the evil wizard Voldemort. While the battle does not destroy the castle, it does damage it significantly. It also manages to draw unlikely participants into combat; for the first time in the school's history, the majority of the upper level student body engages in open combat, as do the house elfs, the school's magical caretakers, and the centaurs who roam the Forbidden Forest.