Platform 9 3/4.

Through this barrier, of course, lies Platform nine and three-quarters, home of the famous Hogwarts Express. There a look back at the barrier reveals it is instead a wrought-iron archway with the words "platform nine and three-quarters," and over the scarlet steam train billowing smoke, a sign announces that the Hogwarts Express departs at eleven o'clock. The platform also has a distinct smell - one which lifts the spirits of young wizards who look forward each summer to the start of term .

Though the platform is normally only used six days a year (round trips for the beginning and end of term, as well as the Christmas and Easter holidays), the platform on those days is awash with activity.

Finally, at 11:00, a whistle sounds announcing the train's departure, and the hiss of the pistons fills the platform as the train begins to move, creaking out of the station as family members stand on the platform and wave their children off to school. Nobody returns to the platform, then, for months - until the end of term, when it once again fills with wizards and a wizened old guard sits by the archway back to the Muggle world, making sure everyone gets home without attracting too much attention.