When I think of Catalonia, I tend to limit my view to Barcelona and its area and all the way to the French border (either Pyrenees or Banyuls).
I recently found out about Amposta situated in the southern part of the region,. It was never on my radar. A visit to the city can be justified by medieval sites such as Torre de la Carrova and lush gardens (the Atanasio Garden pictured here) to name a couple of its strong attractions. 
The area also offers 7 Eco Tourist routes.
The proximity of the Ebro Delta Natural Reserve adds to its attraction. The Ebro Delta is home to the second largest wetlands of the Mediterranean after Camargue.
Spain I can recall: My Andalusian roots brought me to Casitas