Right next to the cathedral is Real Alcázar de Seville. It is the oldest royal palace still in use in Europe and fellow GoT fans will probably recognise it as the water gardens of Dorne. It’s stunning and definitely a highlight of Seville. Make sure you book in advance online though otherwise the queue to get in get can be huge. It’s a really beautiful site with stunning ancients courtyards and amazing gardens. You definitely need at least a good afternoon to do properly.