Moaning Myrtle's Bathroom

It is located at the second floor of Hogwarts which was once used by female students until Moaning Myrtle was killed by Voldemort through the Basillisk's eyes. It is now out of order ever since Myrtle came haunting the bathroom and students avoid it. The sink is the entrance to the Chamber of Secrets, which is opened by Parseltongue. It was used by Tom Riddle to open the Chamber of Secrets, Harry Potter, Ron Weasley and Hermione Granger as a hiding place to brew Polyjuice Potion, used by Harry Potter, Ron Weasley and Gilderoy Lockhart to open the Chamber of Secrets and used again by Ron Weasley and Hermione Granger to open the Chamber of Secrets and destroy Helga Hufflepuff's Cup with a Basillisk fang.