Hogwarts: An Incomplete and Unreliable Guide
J. K. Rowling (Robert Galbraith)Quotes
Perhaps no students (even including Harry Potter, Ron Weasley, Hermione Granger and Tom Riddle) have ever explored the castle and grounds of Hogwarts as thoroughly and illicitly as the four creators and contributors to the Marauder's Map: James Potter, Sirius Black, Remus Lupin and Peter Pettigrew.
The Marauder's Map is lasting testimony to the advanced magical ability of the four friends who included Harry Potter's father, godfather and favourite teacher.
Fred and George Weasley gave him something James Potter and his friends made when they were at school - the Marauder's Map. 'I solemnly swear that I am up to no good.'
...This raised interesting question of how many other fractional platforms lay between the whole-numbered platforms at King's Cross, and I concluded that there were probably quite a few.
The Great Lake
There are Grindylows (vicious little water damons), merpeople (of a hardy Scottish strain) and a giant squid, which is semi-domisticated and permits students to tickle its tentacles on sunny days, when it basks in the shallows.
We leave you with these small pieces of advice: tread carefully when you using a Time-Turner, stop searching for the Chamber of Secrets - unless you're a Parselmouth - and don't linger too long before the Mirror of Erised.
Mirror of Erised - J. K. Rowling's Thoughts
The advice to "hold on to your dreams" is all well and good, but there comes a point when holding on to your dreams becomes unhelpful and even unhealthy.