Peñíscola served as the exterior of Meereen, the slave city ruled by Daenerys Targaryen, in Seasons 5 and 6 of Game of Thrones. The castle gate, the walls of the old town, and the harbour at the base of the rock all appear in the show. The pyramid scenes were added digitally, but the stone streets, arches, and the view from the battlements are unmistakably Peñíscola.
The town leans into the association — there are GoT-themed guided tours, a small exhibit near the harbour, and more than a few shops selling dragon merchandise. If you have seen the show, the locations are immediately recognisable and genuinely worth seeking out. If you haven't, the medieval fabric is impressive enough on its own terms.
The most filmed spot is the main gate and the walls immediately above the harbour, where several crowd scenes were shot. The castle courtyard also features in a few episodes.