Halloween Underground Cinema at Cardiff Castle is an immersive cinematic experience held in the medieval, stone-vaulted Undercroft. This seasonal activity, by Darkened Rooms, features horror film screenings, spooky decorations, and eerie ambience to create a thrilling Halloween atmosphere for all. The Descent (18, 95 mins) A group of six friends go on a caving expedition in the Appalachian Mountains, but after a tunnel caves in, they find themselves trapped deep below the surface of the earth. And they’re not alone… This should be uniquely terrifying experience in Cardiff Castle’s Underground Cinema!