La Casa del Abuelo is a historic tavern in Barrio de las Letras that has been serving traditional Spanish cuisine since 1906. It is famous for its gambas al ajillo (garlic shrimp) and grilled prawns. The tavern has a cozy and rustic atmosphere, with wooden beams and vintage photos adorning the walls. La Casa del Abuelo is a must-visit for those looking to experience authentic Spanish flavors.