“Mischief managed” – that is what you say to the map after you’ve used it so that it will hide its contents. This is the very popular map used in the magical world of Harry Potter that is said to be very helpful to those who want to explore the vastness of Hogwarts School. The Marauder’s Map was made between 1975 and 1978 by Remus Lupin, James Potter, Peter Pettigrew and Sirius Black (termed as the “Marauders”, hence the name) during their stay in Hogwarts. This map shows every room these four guys know in Hogwarts. For those who are familiar with the Harry Potter story, the Room of Requirement and Chamber of Secrets aren’t in the map because probably the Marauders don’t know of their existence.
Aside from showing rooms of Hogwarts, this map can show the locations of all the people inside the walls of Hogwarts, even it there are magically concealed from the environment. It’s like a really, really advance GPS device on paper. Plus, it is password-protected, so only the people who know the password can use it.
Those who are up to no good will definitely have fun using this map. To know every passage in Hogwarts is a treasure itself because only a handful does have that knowledge. And with this knowledge, one would be able to explore the magic and history bound in the walls of Hogwarts. He’d be able to use it to save his life to some events even, (i.e. the Battle of Hogwarts, Harry Potter and the Deathly Hallows).
But every power does have limitations. This map will not be able to show those rooms unknown to its authors during the time it was made. That’s why the Chamber of Secrets is not on the map – none of the authors have access on that room (i.e. Parselmouth). As for the Room of Requirements, the room is magically unplottable.
Below is an attempted version of a muggle to reproduce a Marauder’s Map. (Meh.)