The greatest number of people attending and participating in a magic lesson held simultaneously at different venues is 2,573 and was achieved by La Fundación Abracadabra de Magos Solidarios (Spain) in 51 Hospitals in Spain, on 10 December 2010.
The lesson included two magical routines, the 'sudden wand' and 'cut & restored bandage'.
Please note: Comments below may relate to previous holders of this record.