There are lots of secret passages at Hogwarts. The main one mentioned in the second book is of course, the passageway to the Chamber of Secrets. This is accessed by a sink in the girls bathroom, which is not connected to the Plumbing system and has a small snake engraved on it. Anybody who can speak parseltounge can ask it to open, and the passage will be revealed.
Please see the following walk through for details on the secret areas. http://www.gamefaqs.com/pc/562014-harry-potter-and-the-chamber-of-secrets/faqs/55157
Harry opened the secret passage with Parseltongue.
The answer is "Moste Potente Potions'.
There are hundreds of paragraphs in Harry Potter and the Chamber of Secrets since a new paragraph begins with every new line of dialogue. Paragraph counts aren't really kept since there are so many of them.
You have to jump on the platform at the top of the stairs. That'll open a secret passage which you can reach by jumping on the Spongify mat.
There are many secrets in Harry Potter. There are secret rooms, like the Chamber of Secrets, the room where the Sorcerer's Stone was held in Hogwarts, and the room where the Mirror of Erised was. There are personal secrets, like the fact that Ron and Hermione were in love. There are repulsive secrets, like the fact that Voldemort had split his soul into 8 pieces (the 8th was unintentional; it was in Harry, so that's why their minds were linked). There are more, but you're going to need to find out those yourself.
The main secret in Harry Potter and the Philosopher's Stone was that the philosopher's stone was being hidden in Hogwarts to protect it.
In the third Game, you can buy them at Fred and George's store or find them in chests. Usually in secret passageways or Hard-to-Get-to places. ~DarkestNyght
Harry Potter 1, Harry Potter 2, Harry Potter 3, Harry Potter 4, Harry Potter 5, Harry Potter 6, Harry Potter 7, Harry Potter 8.
Hidden doors in walls may reveal secret passageways, hidden rooms, valuable treasures, confidential documents, or evidence of past events.
Expecto Patronum (against dementors), Waddiwasi (against Peeves), Riddikulus (against Boggarts), Dissendium(to reveal secret passageways)............ Basically, what do you want?
They could have secret passageways leading out.