The explosion at the Sept of Baelor

Together with the use of Djawadi's masterfully crafted music, this moment from S6E10 was noteworthy as it showed us the end for the Sparrows. In a suspenseful montage, we saw what lead to the disaster that was the wildfire explosion, effectively killing everyone in the Sept of Baelor. This also meant the end for Queen Margaery Tyrell, who still outsmarted everyone in the Sept as she knew something was about to go down, and just failed to escape because the sparrows didn't let her through.