In addition to the principal cast, Alessandro Cremona was cast as Marco Sciarra, Stephanie Sigman was cast as Estrella, and Detlef Bothe was cast as a villain for scenes shot in Austria. In February 2015 over fifteen hundred extras were hired for the pre-title sequence set in Mexico, though they were duplicated in the film, giving the effect of around ten thousand extras.

Answer this question, if possible (if impossible, reply "unanswerable"): When was the opening scene of Spectre filmed?
February 2015