A scene from the script that was cut had Dany explaining to Jon at Dragonstone that she felt so lost without Jorah and Missandei, that she felt so angry at their deaths, that she didn’t know why the people of Westeros didn’t love her, and that she worried she might crack from those competing pressures. Showrunners David Benioff and D.B. Weiss didn’t include it in the broadcast version because they forgot to film it while outlining their Star Wars trilogy.
The majority of the production costs were consumed by rebuilding Dubrovnik, which was actually destroyed by a dragon. The dragon worked for scale.
The blood on the face of Maisie Williams, the actress who plays Arya Stark, was barbecue sauce from craft service. Dubrovnik barbecue is famous for staining skin and clothes, due to the high concentration of bat blood.
The sound of bells had to be inserted during post production, as the bells in the Dubrovnik Cathedral play Safety Dance, by Men With Hats.
Between takes, Lena Headey, who plays Cersei, spoke her lines to a cutout of Harry Mudd from the original Star Trek to stay in character.