(Spoilers ahead, obviously.) To capture horses running at full tilt across the battlefield, director Miguel Sapochnik relied on a specialized remote controlled camera rig (dubbed the "Russian Arm") that was sitting atop a Land Rover. And to turn its hundreds of extras into thousands, the show's VFX artists implemented some heavy-duty crowd replication. There were also digital effects throughout the battle, including a swarm of arrows filling and falling from the sky, as well as composite effects weaved in to safely show things like soldiers flying off horses

Oh, and if you were wondering, that wonderful shot of Jon Snow confronting a wall of enemy soldiers on horseback, entirely on his own, was completely real.