What is significant about Harry Potter and the Chamber of Secrets?

Answer 1

It is the myth about a chamber called Chamber of Secrets made by Salazar Slytherin when he was one of the Headmasters of Hogwarts. Tom Riddle, (who is now called as Lord Voldemort) has a diary with a part of his soul in it, possessed Ginny Weasley ( Ron's younger sister) and made her re-open the Chamber of Secrets, which was sealed years ago.

Lord Voldemort then made Ginny awake the Basilisk which was living in the Chamber of Secrets to go up to Hogwarts and kill the students, starting from Muggle-borns, as Voldemort hates them most.

Fortunately, the students the Basilisk tried to kill wasn't all successful. When the Basilisk "killed" the students were indirectly.

Example, when the Basilisk tried to "kill" Flich's cat, it was looking at the pool of water on the ground when the Basilisk was looking at the cat, so it was indirectly.