Doomsday Castle is a reality television series on National Geographic Channel, that was canceled in 2013, showing the lives of Brenton Bruns and his five children preparing for the end of the world, in a castle he has built near Pickens, South Carolina. The show is a spin-off of Doomsday Preppers; Bruns and his castle were originally featured on the season 2 episode "No Such Thing as a Fair Fight".

Bruns says he built a castle to survive an electromagnetic pulse, since a castle can survive without electricity and defend against raiders. It started as a bunker in 1999, and is continuously being added to. Bruns states that his property is covered with booby traps, and his neighbors are "serious preppers with lots of guns".