If you are visiting London and want a moment of pure silliness head for the main concourse of Kings Cross Station. First you see the small queue and a crowd of folks taking photos with cell phones, then you hear short bursts of loud laughter and finally PLATFORM 9 3/4 is revealed.
The assistant (who seems to have endless patience) gives you a scarf and holds the end out of shot to make it look like its blowing in the wind. You pose and your friends and family take a picture of you pushing your luggage trolley on your way to Hogwarts.
This scene, repeated throughout the day, is pure, joyous, free theatre. Folks from every nationality share their moment of childish delight and laughter, embracing the possibility of fantasy and magical escape.
It makes us giggle and gets our ten out of ten for free London tourist destinations every time