Platform Nine And Three Quarters

Platform nine and 3/4 is the platform on which carries the students of Hogwarts School of Witchcraft and Wizardry. It is invisible to the muggle eye and is reached by walking through the barrier seperating platform 9 and 10

It was first seen in Harry Potter and the Sorcerers Stone, the first Harry Potter.

To get on the platform, one must run straight at the barrier. once passed through, they find themselves standing on the platform of the Hogwarts Express.

In Harry Potter and the Chamber of Secrets, Harry is warned by a majical creature named Dobby - a house elf that Harry should not go back to Hogwarts. on trying to keep Harry away from Hogwarts, he causes the barrier to block Harry and Ron out from getting to the majical world.

"Harry Potter must not go back to Hogwarts School of Witchcraft and Wizardry!"

-Dobby

Harry and Ron get around this obstacle by taking Ron's flying car - only to be seen by muggles and nearly getting suspended from the school

"How dare you take that car!"

-Molly Weasley