During the past easter of 2017, I did with a friend of mine El Cami de Ronda (Catalan) or El Camino de Ronda (Spanish). It was a 5 days trek through the Costa Brava (Girona), to one of the most famous trekking routes of the Mediterranean.
This coastal path got formed during the 19th century, due to small footprints through the cliffs. But during the 20th century, it was used by the Guardia Civil (Spanish military forces) to prevent smuggling. Nowadays, this beautiful trekking route, has only leisure purposes. You can either walk it by parts or in a row.
You can start the trekking route at the North of the Girona province, in Portbou, and go until the South of the Tarragona Province, in Ulldecona. Apparently it actually goes all the way down to Malaga, in Andalusia. The difference between regions is big, and the worst one is the part of the Valencian Community, which is not signposted at all. The length of the whole route of El Cami de Ronda through Catalonia is 583 kilometers, and you could check the itinerary of the Catalan path here.