In Harry Potters 1st year, the Sorcerer's Stone was hidden in the third floor corridor. Harry stopped Professor Quirrell from obtaining it. In his 2nd year, the Chamber of Secrets was open once more, though nobody died. Harry went into the chamber to rescue a student taken there, and killed the Basilisk. In Harry's 3rd year, Sirius Black attempted to penetrate Hogwarts, but eventually was revealed to be innocent. In his 4th year, the Triwizard Tournament was hosted at Hogwarts. At the end of the tournament, Lord Voldemort rose again. In his 5th year, he started an illegal student group called Dumbledore's Army in the Room of Requirement. In his 6th year, Death Eaters penetrated Hogwarts and eventually managed to kill Dumbledore. In Harry's 7th year, there was a Battle of Hogwarts. Hogwarts won against the invading Dark Lord and his forces.