The Great Trafalgar Square Freeze The day London froze. Inspired by improv everywhere and made a reality by 100's of volunteers. At exactly 3:30pm on a secret cue, The day London froze. Inspired by improv everywhere and made a reality by 100's of volunteers. At exactly 3:30pm on a secret cue, almost everyone in the square froze. The few bewildered tourists didn't know what was happening. For 5 minutes the participants held their positions, and then magically everyone unfroze. Why? Well, why not.