Because over 500 school children donned the distinctive hats, capes and glasses to dress up as their favourite fictional character on World Book Day. That is a lot of wizards - and witches - under one roof!
In fact, there was so many of them, the 512 Year 7 and 8 pupils of Tanbridge House secondary school managed to break the world record for the most amount of Harry Potters in one place.
The record previously stood at 250 but the students from Horsham in West Sussex overtook it easily.
The man behind the brilliant idea and learning development manager at the school, Ben Baker, said: "It's amazing- we are world record holders!
"It's a bit of a relief to have finally got the nod and we were very lucky with the weather because, with so many people, we were forced to do this outside."
Now that's magic!
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