Question 664: Don't sit through this sitter

Though the exact origin of 'X' is unknown some reports claim that in the 1960s, in Monterrey, during a game between Tigres and Rayados, 'X' was created in the half time. The crowd was anxious, and the organizers were doing games and throwing football balls as presents in the half time because players took a lot of time returning to the field. That made people do the 'X'. But whatever its origin, by the mid-1980s the practice was widespread throughout North America. Finally, it gained worldwide notice, and the specific name 'X', during ________ in ______ at the Estadio Universitario in Monterrey, 1986. ( if this is any clue, the last blank is pretty significant)

Answer: The Mexican Wave